How much is too much...

Basically I have one question and one question only. Give me one rule of thumb when buying a Power Amp. What are the does and does nots :) of buying a power amp?
Buy an amp that has enough power to drive your speakers in your room. Less efficent speakers and a large room will need more power.

Never buy ANY equipment on some magazine review or someone else's opinion. Go listen for yourself and buy the one that sounds the best to you. Insure that you can have an extended listening session. I made the mistake purchasing a bright system when I first got into this. Only if I would have listened to the system for an hour or so I probably would not have made this mistake.
It should be a McIntosh 275. Then you won't have to play the upgrade game.
Heh, this is a tough one. One manufactures 100wpc sounds totally different then the next one. It greatly depends on a few very important factors:

Speakers efficentcy, room size, amperage output from a given amplifier, and finally, source material.

How loud do you want it to be? What kind of music do you prefer? Are you a bass, mid or highs person?

Much of this revolves around personal preferance. Even so, a good amplfier will usually, atleast, halve it's output as the load presented to it drops, for example:

100wpc into 8ohms, 150 into 4ohms and 200 into 2 ohms.

Remember as currant rises, voltage drops, and visa versa.

Really good amplfiers not only perfom to the above, and, far beyond this, but maitain the same "musical qualities" as they do at low output levels until they near their respective clipping power. Amperage, IMHO, is more important than wattage, this beyond a certain point of course- say 50wpc as a starting point for moderate output from say a 90db rated speaker system, and a good quality amplfier of course.

The biggest upgrade I have ever actually recieved a "thrill" factor from was in the source, in my case, my CD player of choice- Audio Refinement (YBA), it smoked my Denon 1650AR, and both my Sony ES players, as well as the previous Rotel I had.

It's up to you, but just remember the above, you'll do fine if you choose with you ears and not "glam factor".
Too little power is more of a problem than too much power.
Excellent answers above. If you could tell us what speakers you will be driving, this would be a good starting point and go from there.
You should buy what sounds best to you, no one elses' opinions matter!
Hi, Banksfriend, when you suggest other peoples opinions don't matter, does that also include your opinion? Forums = other opinions. But I understand & agree with you that your suggesting Thegoldenear should go with what sounds the best to him. I am quite certain that is how it will turn out in the end anyway. Good deal!
- tube or solid state.....personal prefence here...tubes generally require more maintance.. alot has to do with matching it to your, and power ( good point - better to have to much than too little)

-relability.. buy from a reliable mfg... chances are you might need service (higher for tube gear)and a mfg that has a good reputation for service and relabilty is REALLY important... if tubes, i would suggest to go with a really long term mfg with a great reputation ( BAT, ARC, Quicksilver) and not a start up company..

single end / dual differential inputs - important to optimize your connections and topology (for true balanced) and iec connection for power cords

impedence- should be considered to match with the pre-amp.

current capability - 100 wpc from a krell/classe/pass is going to have a differnt presenation than 100 wpc from a rotel/parasound/adcom. with that being said 100 wpc from most tube amps will even have more current than a good solid state amp (except the bass -"generally speaking")

mono block vs stereo - depending on load, design, and budget...mono blocks "generally" sound better and look really cool

there are more points - hope this helps out
Yes, my opinion does not matter... to anyone but me.
Most problems occur at the frequency extremes. Most amps do the midrange pretty good but can have shrill HF or bass can be weak or boom.
this is the problem a really good amp that would support a rms of 200 watts (which is suppose to stop clipping) is very expensive. Which is fine but I dont wanna over pay if 100watts would do just fine. The speakers that I may buy are the QUAD 22L or Triangles Antals not sure yet. My listening room is 25'10" X 13'3" with 8' 6" ceiling height.
Hi Thegoldenear, although I have not personally heard either one of the speakers you mentioned above, I would strongly suggest that you go with efficient speakers if you don't want to invest in costlier amps that are over 100 watts per channel. I am guessing that the above mentioned speakers are efficient?

In regards to amplification I would have to agree with Banksfriend, once you buy speakers, try different amps to see what sound best suits you. That is why Audiogon exists, you can buy & sell till you find what your looking for. If you were to run a thread on whats the best amplifier, you will get at least a 100 different answers. If I could take the best attributes of each different amp I have heard and combine them into one amp I would have the perfect amplifier. For the forementioned reasons, set rules don't apply.

The best suggestion I can make is, do your research and read the reviews on any given amp to get an idea what most people think, what speakers their using & try to avoid impulse buying which can be a tall order for some of us. But if push comes to shove I would recommend Odyssey (Germany's Symphonic Line but USA made) or the McCormacks (The iron fist in a velvet glove), both being well reviewed, and well loved by many audiophiles without breaking the bank. Also I love the newer Mcintosh but a little spendier.
you should first determine the efficiency of your speaker. this maybe obtained form the manufacturer. then assess the size of your of your room. Is it alive or dead? walk through your room and clap your hands. is the sound loud and crisp or is it muffled?
What type of music do you like? Rock and classical require more power than jazz or chamber music.
Typically tube amps have a greater percieved loudness than solid state. If you are serious bass fan I strongly reccomend biamping.
Because amplifier power is such a huge selling point most manufacturers manipulate the rating to achieve the maximum watts per channel. this means you will have to make your own evaluation. You can rely on certain companies like krell or bryston just to name two.
A lot of people think spec's don't matter. I think you eliminatwe those amps that are not technically correct.then listen to the speaker amp combo in your room.
The Triangle Antals are easy to drive well, and only draw a little extra current at the low end of the scale.
So a well designed amp spec'd at 50-100W with a good PS should do famously.

Symphonic Line is one amp that sounds excellent with these spkrs, so the Odyssey mentioned above may be worthy of seious consideration.
wow thanks guys you've helped a great deal, have a happy thanksgiving
Caveat, these are just "Old Wives Tails" of audio, they are not concrete rules, "Just Rule(s) of Thumb": (1) double the power of the loudspeakers manufacturerer's minimum suggested power recommendation, (2) for high impedance speakers use tubes, for low impedance speakers use solid state.