From your description, it sounds like you are describing the Sennheiser HD650. I just got a pair for Christmas and I really like them. I find them to be pretty neutral with very good, but not overpowering bass. They are also very much non-fatiguing IMHO. I'm very sensitive to boomy bass and hot treble and I can listen to the HD650s for hours without fatigue.
I'm currently just using a NuForce Icon as head amp/DAC as I had one laying around. It works great. However, do some reading over on the Head-Fi site and you will get lots of other recommendations for headphone amps to use with the HD650s.
I bought my pair over on the big auction site. There is a seller there who sells lots of them (new, in retail box) for a great price.
Also, according to the folks on Head-Fi forum, you can do lots of mods to increase the performance, if you want. Many folks remove foam, re-cable, convert to balanced operation, etc. and generally tweak the heck out of them. For now, I'm perfectly content and don't plan to do anything to mine. I'm just enjoying listening to them.
I have to recommend a AKG 701, just amazing sound. Also, you can find Lehman headphone amps used for about $500. Two tips:
1. Buy the AKG's from a DJ site, they heavly discount.'
2. Check out headfi.org, list serve devoted to headphones
AKG 702 and Heed Can Amp are a great combo for less than that money...want even better for a few hundred more? Burson HA160 ($699) and AKG 702 ( $250) will light you up very well.
If you decide to go with the HD 650, J & R is the best place to shop, the current market price @ $499.00 is way overpriced. Talk to Alex @ J &R , he will get you a huge discount.
Also, Electronic Expo always has coupon that will save you from 20 to 30 %. I bought the Shure 440 for my son birthday for less than $70.00 including shipping.
The AKG 702 should not cost you more than $250.00 if you look hard enough.
The Beyer has along line of fans but their treble are kind of harsh that I need to avoid. I can handle the bright top of the AKG 702 but the Beyer sound house is way above my taste while the Senn is a bit colored and dark.
Just my 2 cents.YMMV,
First, go to headfi, the website. It is all about headphone listening and amps. You will get more feedback there than here due to its specialty based site. That being said, AudiogoN is the best website in the world!
That being said, headphones are very subjective and one person's likes are very different than another person's and many people have limited experience and therefore can only make recommendations based on very restricted listening. Headfi you will find true afficianados and more experienced feedback.
things to consider:
Do you want to take you phones and amp with you when you travel?
What do you have access to listen to locally (stores, other members of this or other sites)?
Open back, closed back, in-ear, etc. . .
I had a couple of pairs of JVC Victors (very nice phones) and sold one pair to a guy who I delivered them to. A real headphone guy. He had 3 headpone amps and about $20K worth of headphones (that's why I delivered them). I got to listen to a lot of different combos and there are huge differences between amps and cans (much more so than with speakers - in general).
Why don't you start out by reporting where you are located, you may be surprised to find other members are open to helping you out (ie. listening to their equipment).
I have Senn HD 600 which are amazing. I went with them over the 650 as most reports were that the two were basically par minus a smidge of bass. I thought about getting a headphone amp, but was quite pleased with the sound from the headphone output on my receiver (a marantz now, and formerly an older Sony ES). They even do ok, but with limited volume, through my iphone or computer.
One word of caution, do not buy from amazon as I tried that and ended up with a defective pair of headphones with a missing serial number. I bought mine from an authorized dealer and paid the extra $30 or $40 over amazon after returning the ones that were defective.
If it is neutral you are after then the HD600's will come closer than the HD650's. The latter emphasize bass a bit more and dip in the treble more than the 600's, and all of that is quite audible. I personally found them damned boring cans mayself, but they are certainly on the neutral side. I listen to all of the material you list and would recommend a more lively can. None that I've tried (and I have tried a few) do absolutely everything right, so you may want to set your priorities among the music you do listen to, as well as the qualities you value from a headphone (bass, treble, soundstage, vocals, etc.). Grado's are not neutral cans, but they certainly can be very enjoyable. If you do enjoy a lot of rock, their RS-1 or HF-2 (I think the latter is only available to Head-fi members from TTVJ.com) might be very fun choices...but not neutral. If you stress the vocals, classical, acoustic thing, I might suggest ATH-W5000, which is a rather warm can as I recall, and is also of the few closed cans that do a very nice job at some sacrifice to soundstaging (a bit overrated on headphones IMO). Choose the amp according to the headphones, just as you would for speakers. My .02 Lincolns on the AKG702 - on three different amps they just did not occur to me to give the music the weight that seems more true - they sounded a bit thin, and are very picky about amplification. They are definitely a lighter, airier sound than the Sennheisers recommended here.
Amp would be the Cayin. Once you have that I would suggest trying different heads till you get the best fit to your listening tastes.
Jax, I do not want to collect another Senn cans ( my HD 280 pro/ HD 595/ HD 650 still have not enought burn-in time yet) BUT the HD 380 seems to have a very high rating. What's your take on the HD 380 pro and the ATH-M 50? Are they all-around good for non critical listening or just hypes?
Andrew- I have no experience with either of the cans you mention. I'm a reluctant headphone user (much prefer speakers) and use them only when my wife requires quiet. Over the past ten years in using cans I've probably gone through as many different headphones, so compared to those who've embraced that hobby with more enthusiasm, my experience is limited. Which is why I'm suggesting you check on Head-fi. In spite of the highly elevated noise ratio, there are still a few folks there who come from a solid base of experience (though, alas, they seem fewer and further between than say, five years ago). If your budget were higher I'd point you to two of my favorites: HD800's and LCD-2's (very different from each other, and the HD800 is like no other Senn can), the latter of which I currently own and enjoy, and the former is what I owned before that. The LCD-2 frequency response is desert-flat up to 1K, and then gets shelved down about 10db and extends out to 20K (so a rather unique response). Other than the slightly recessed treble, they occur to me as very neutral cans. If you are way into soundstage and treble, the HD800's might be your cup'O'joe. My complaint about them is the soundstage can almost be a bit disorienting at times, and the treble spike tends to emphasize sibilance more than I'd like. Still, they are outstanding cans. I don't think there is a perfect headphone that does everything perfectly. One sleeper can that you may be able to find on the used market at a decent price, is Sony's MDR-CD3000 (not to be confused with the other 3000 models). I thought that was a very nice pair of headphones that was enjoyable to listen to most material through. I used them with a Berning Micro-ZOTL amp, which paired off really well and is a great amp with the right cans. They seem to be harder to come by these days though, and prices have gone up on them.