I have found the more power the better, they come to life with power (current)
i do not know your amp so can not comment but you may be satisfied with less power if you do not listen too loud 
you can answer your own question by auditioning amps from low to high power, by that i mean, from 10 watts to 500 watts. i own 1.6s. i have heard a 4 watt single ended amp, a 350 watt class a am0p, a 500 watt class d and others, mainly tubed, having varied power ratings.
only you can decide what is satisfactory to our ears. 

When I had 1.6's I drove them with 250 watts they were OK but always seemed like they wanted more (which you have). My guess is the Mac is going to be fine. Like Philjolet stated they like "high current" amps (maximum output current) 
whats a good HIGH CURRENT AMP 
My MG1.6 sounded best when driven with a 600 watt (4 ohm) digital amp. CarverPro ZR1600. They sound almost as good with the audiophileapproved CI D200, also digital, and good for 350 watts.
Maggies can sound deceptively good with much lower power, but you won't know what you are missing. 
When I had the 1.6's, I drove them with Classe' 400watt monoblocs. That was enough juice! 
The 'hi current' thing with Maggies may be somewhat of a 'red herring'...........And I have been an owner for 25 years..starting with MG1s...driven by a 60/side Kenwood KA7100! I currently own 1.6s The reason I say that is that the Maggie has a 4amp fuse on the midtweeter. 4amps at even 70volts (a lot) is still 'only' 280 watts....I'll admit to nearly 2x that when adding the low frequency part of the panel. Given a fuses response time,(pretty quick) I'd be hard pressed to justify an amp with a (claimed) 'instant' current capacity of say 40 or 50 amps. My ICE power of 250x2 at 4 ohms seems way more than enough juice, and I suspect a wattmeter will show my average use as low as a total of less than 20 watts, with an empty house and nobody to annoy with loud music. That being said, Magnepan uses Bryston for there demos. A 3b or 4b (SST is latest) should do the trick. 
Magfan...Its Voltage squared divided by ohms load.
70 volts would be 1225 watts.
I actually made some measurements while my MG1.6 was playing very very loud music. My objective was to see if my 600 watt amp was overkill. I saw peak voltage at a level that would correspond to an amp of about 600 watts. Of course, at more moderate SPL and during most of the music the voltage peak level was more like 12 or 14 watts. Based on my findings I decided that 350 watt CI D200 amps would be OK, and I applied the ZR1600s to other tasks. By the way, my experiment was done with the Maggies seeing only 50Hz and up. 
"That being said, Magnepan uses Bryston for there demos" .....and ARC 
Good experiment with some measures. Now that I think about it....a speaker with a hipowered amp can see 2x the voltage I mentioned....an amp typically has 2 power rails....plus / minus so the difference between the rails is what the speaker sees. My International Rectifier class 'd' (for play) has 2 rails with a max of +/ 55v.
What happened to P=IE? By this method.....the max current to the panel (fuse limited to 4 amps, 600hz and up) is as I wrote in my last post.
My Formula, and yours are both correct...My assumptions couldn't be right.
http://www.the12volt.com/ohm/ohmslaw.asp
So I suspect I made a bad assumption of voltage to the panel. Fact is, the darn thing has a 4 amp fuse which sets an upper limit on amp current, No? If the panel can sustain double the fuses rating and as know, is pretty flat at 4ohms....with a nasty peak at the 600hz xover, that should set an upper limit to power. The Panel maxes out at about 18 ohms at 600hz and over 6 ohms from 200 to 2000 hz.
Other than a math problem, What is the problem with the rest of my post?
Also, now that I look at an impedence / phase chart of the 1.6, I realize that even for this speaker (fairly benign), the problem is pretty complicated. If you take the 18ohm at 600hz, and ASSUME a max of 5 amps at that frequency, that is Isq=25 x 18ohms = 450 watts at 600hz. Even 7 amps yields 'only' 882 watts....clearly a deal breaker at that frequency. it gets weird when considering music.
http://stereophile.com/floorloudspeakers/595/index6.html
If I had the time/tools ( I am immediately sending away for a KillAWatt.....<20$@newegg) I will measure the entire power needed by my fairly efficient GCC250......than use some kind of fudge factor to determine power to the speaker. The neighbors have aloud treat instore for them.....!
Thanks, Eldartford for making me rethink this. My conclusion, however, remains the same. It is very likely that HiCurrent is a Magnepan redherring, given the limits imposed by the fuse and physics.... 
Eldartford ... I actually made some measurements while my MG1.6 was playing very very loud music. How did you do this? I would love to know what my speakers are demanding during my play. 
Rockadanny...I simply used a digital voltmeter, which makes a measurement about once per second. Careful observation will yield a result very near the maximum brief rms voltage. Then the peak is reasonably estimated as 1.4 times the rms. A peakreading meter would be better, and an oscilloscope would be best. 
Magfan...True that Watts = E * I,
But I = E/R
So Watts = E * E / R.
Also, the "rail" voltages get output one at a time. PlusVtoground OR MinusVtoground. Never PlusV to MinusV.
Also, the 4 amp fuse is at 120 volts. It can yield much greater current at the lower voltage delivered to the speaker via the amplifier. 
Eldartford, is this a test? Sorry, but as near as I can determine, a fuse can be used at any voltage below its rating. In the 'hydraulic' model, volts is pressure and amps is a quantity....somewhat independent. If your contention were true, the fuse would provide little or no protection, since you could somehow devise an amplifier which would output very low voltage @ very hi current, and still be within your definition of a fuses ratings. A fuse doesn't dissipate 'watts'...
My bad with my first post was poor choice of numbers. I still maintain that hicurrent to maggies is somewhat of a redherring. Please design a scenario where a maggie can receive say...20 amps at whatever voltage you choose. Than, find me an amp that produces such and not 'pop' the fuse. Also, with the voltage rails at + a (given) voltage, this represents the maximum voltage the speakers can see. The absolute value of +50 volts is 100v Without Sign. (absolute value definition) The only thing left to argue about is 'how large a spike a fuse can take over what time period' http://www.circuitprotection.ca/fuseology.html#Top Link has useful chart and definitions. Go to the bottom of the page and look at 'Voltage Ratings'...that a 250v fuse can safely be used in a 125v circuit negates your arguement. 
Magfan...Stop and think about what I said. Sometimes the voltage at the hot (red) terminal of your amp may be +70, and sometimes it may be 70 but the black terminal is always 0, so the speaker never sees more than 70 volts across it.
80 volts applied to a 4 ohm Maggie would result in 20 amps (assuming the amp could deliver this). The power would be 1600 watts, so it better not be applied very long!
At 120 volts 1600 watts is 13.33 amps. If course no amp is 100 percent efficient, so the 120 volt line fuse would need to be a higher value. If, however, you had an amp running on 240 volt power, 1600 watts would necessitate only 6.67 amps plus some for amp inefficiency.
4 amps at 120 volts represents 480 watts. For simplicity let's assume the amp is 100 percent efficient. If you had a speaker with a 1 ohm impedance 22 volts would be 480 watts. The current drawn would be 22 amps (and all from that 4 amp fuse in the 120 volt line).
Your remarks about fuse voltage ratings makes no sense. I never said anything about fuse voltage rating. The voltage rating exists to protect against arcing after the fuse blows which might occur if the voltage is greater than the fuse rating. 
So, what is the bottom line? Are Maggies 'current hogs' or not? Doesn't seem that no matter how the numbers are tortured that you can get more than 6 or 7 amps thru them, adding 4amp mid/tweet and 3 or 4 for the low freq. Based on math we have already agreed to....E=IR gives about 50 volts. I am using 6ohms....and 8 amps. (rounded up) Than P=E2/R gives just over 400 watts....(round down of <5%) The reason for 6 ohms, is the 18ohm peak at 600hz and the 6ohms from 200hz to 2khz, where MUCH music power resides. The actual musical average MAY be higher...'weighted' for frequency. This would result in a higher power requirement at 'red line'. It appears that a good amp of upper to hi end power rating is more than adequate. Choose your presentation and have fun. Rotel? sure......Mac? no problem.......Krell yep,if you have the coin.....Bryston dream on (pant pant)
One puzzle, though. You said:: "Also, the 4 amp fuse is at 120 volts. It can yield much greater current at the lower voltage delivered to the speaker via the amplifier."
Could you please elaborate or explain? It SEEMS to say that a fuse running at lower than rated voltage can pass more current...??? 
Magfan...If we use 6 ohms (as you do) I agree with your 400 watts. However, I was under the impression that MG1.6 were a pretty flat 4 ohms, and resistive to boot. Using 4 ohms and your 50 volts gives 625 watts.
A fuse blows because of I*R heating. Voltage doesn't matter. How long it takes to blow a fuse depends on how high the current is. The rating of a fuse, eg: 4 amps, is the current it will carry forever without blowing. Most fuses actually carry about 1.2 times their rating for quite a while, and twice their rating briefly. "Fast blow" and "Slow blow" fuse types are designed to modify these typical characteristics. 
Eldartford, please check out the Stereophile review I linked a few posts back. The Maggie is INDEED quite flat at just over 4 ohms. Only fly in the ointment is the 18ohm peak at the 600hz xover and the fact that it is 6ohms or better from 200hz to 2khz. This is, of course, a very important area for music where much of the energy resides. Phase angles are also highest in and near this range. Let's not go into that! We are dealing primarily with good quality amps here and these numbers should present no problem to the grade of amp a Maggie owner would typically buy.....agreed?
Agreed about fuse and ratings and actual capacity. This is addressed in the other link I provided. There is a 3rd catagory of fuse....a Really fast blow. This element has slightly higher resistence that the std fuse, but I know nothing past that. Maybe for use in very critical applications and 'delicate' circuits? The fact that a fuse is not a 'brick wall' device probably means 2x power, short term or 3db. And, since R (impedence, in this case) is 'fixed', it's gotta come out of the IE part of the equation...You can only get so much voltage from an amp, limited by the PS, so amps it is!
No wonder my electric bill has skyrocketed.
I threw a dart and chose 6 ohms. YMMV, of course. I believe you were on to something a few posts ago. MEASURE is the way to figure this out. Since music is very complex, there are no easy answers. A string quartet and pipe organ played at a similar spl should have drastically different power requirements....
But, for Pete's sake, how loud do you want it? I must be getting old, but I give up somewhere south of NoseBleed!
Please post some more measures............. 
thanks guys for all the info I have my maggies hooked up i am realy happy with them i find that the two ohm taps on the mac mc352 work the best it just sounds better to me than the 4 ohm tap the music is more detailed thanks ALL very much majic 
I have some experience with really, really, realy, fast fuses! They were to protect transistors in a very expensive and hard to repair motor drive circuit in a missile guidance system. Turns out, there are fuses that are fast enough to protect transistors, but they are themselves transistors, and they cost more than what they protect. It was worthwhile in this case to use the fuses because the cost to repair a blown circuit, reassemble and retest the guidance system would have run to tens of thousands of dollars. Better to replace the thousand dollar fuse. 
Magfan...Interesting about the impedance plot of the MG1.6.
I did an upgrade to the crossovers in my MG1.6...same design just better parts, like air core inductors. I was surprised to find that the high and low frequency crossover slopes were not only different, but the crossover frequencies were significantly different also. I seem to remember that the LF was electrically rolled off well below where the HF cuts in, and this would result in an impedance increase through the gap. Magnepan does a lot of proprietary tweeking to achieve flat frequency response, and the crossover design is part of it.
This is why I have serious doubts about the wisdom of biamping Maggies using an electronic crossover. 
any one can you explian what is happening when i use the 2omh taps on my amp i get the same out put as the 4omh taps but the meters are staying way lower in the 2omh tap i need more gain on my preamp but over all it seems to sound better useing the 2omh and these are 4omh speakers 
Eldartford, what upgrade parts did you use? The stock Solons are reasonably well recieved for a total of 25$ worth of caps for the pair. How much do you have to spend for Better? Also, I have looked up AirCore inductor calculators and it seems to duplicate the stock .4ohm, you need 13ga wire..... what exactly did you do, or did you purchase prewounds?
The Maggie Xover is pretty neat and simple. The HiPass is a simple 2nd order/6db/octave while the Lopass is a 3rd order....and is phase inverted to the tweeter!
I know nothing, not even enough to fakeit about external xovers. If anyone has any luck....and I have seen some on the MagnePan Users Group pages, that would be deluxe. The MUG site is a wealth of real info from a real bunch of addicts. The person also known as Peter Gun does some amazing things...including mounding the panels backwards, designing complete frames and extensive xover mods. Well worth a viewing. I couldn't pass the physical. Good listening..................... Remember:: Too much is NEVER enough. 
I am late to this, but with all of the different amps I have used with Maggies, the higher the power the better. I had a Parasound a21 with my 1.6's when I had them and I thought I was in heaven, until on a suggestion I bought an Innersound ESL (now Sanders Sound) and it changed the whole complextion of the sound. Much deeper, more well rounded and fuller, with extended highs.
I think the Ice and digital amps are a great match for these speakers (Bel Canto, Innersound, Spectron) but for tordial type amps you need massive power and my experience is they are tougher to match (Bryston, Parasound and Cary Audio are the best I have heard).
Good luck, sorry to answer so late. 

I'm using ARC 150.2 Tripath amp for my 1.6's and it's wonderful. 300 watts into 4 ohms. Better than Bryston 3BST to my ears. Paired with AI Mod 3A preamp. Match made in heaven!!! I have a Vandersteen sub as well which opens up the soundstage even more. 