Best multichannel amp for music?

Sounds like you're asking for a multichannel amp with killer bass, and without the cold sound of many traditional high-power amps.

I have used the Nuforce MCH-2C7, also available in 3, and 5 channels (which I can switch down to stereo, using the remote, for my serious 2 channel listening).

I find the NuForce MCH to have the qualities you are asking for: tight, deep well controlled bass, with warm tonality... and you can add world-class dimensionality.

The NuForce multichannels have an impressively beefy chassis, but offer the same modules and sound quality as their much awarded mono amps.

I don't see any used here, today, but since their products are close to your price range new, and you can try them for 30 days free, I suggest contacting them directly.

I don't think you will be disappointed.

I have a Plinius Odeon it has the punch and the sound is very detailed. I set up my home theather just for music. The amp is important but the other compents are necessary to get right also.
if your interested e-mail me and i can give you all the details

Parasound HCA-2205A Read the reviews

I was going down the same path, and went through Theta Intrepid, Proceed HPA, and EAD PM2000. Some of the amps I've used were pretty good. But they didn't provide the very last few bits of the musical satisfaction, namely the presense, detail, and the feeling that "you are there". Somewhat understandable, as the multi channel amps are targeted mainly for HT. The vast majority of HT users (there are exceptions, such as I am) are either not interested in high res music, or don't listen to music critically, and the multi channel amps reflect that.

An alternative path that I'm taking is two chassis system that consist of a two channel amp and a three channel amp. Or you can use three two channel amps, or five mono blocks, or what suits you. The point is there are much more selection available _way_more_, if you go this route. The downside is more rack space, potentially inferior voice matching among the speakers.

I currently have Pass X3 for three front channels, and Aragon 8002 for the rears. The current set up is much more musically satisfying than any other 5 channel amps that I had in my system. My rear speakers are already mismatched from my fronts, and considering how much musical information comes out of the surround speakers I really don't care about front / rear mismatch. I would eventually get a Pass X.5 for front left/right, and set up X3 to power the center and the rears. The slight mismatch between the center and the fronts is still not too important because the center speaker is already mismatched. It's from the same manufacturer but not an identical speaker. Even if I use identical speakers all around, the room acoustics will throw in some variation in the sounds coming out of the speakers.

If you are truly concerned with voice matching all the speakers, you can use a processor utilizing Audyssey RoomEQ instead of trying to match it with a multi channel amp. Audyssey will do a much better job, plus you get to choose your favorite two channel amp for music.

The Plinius Odean is something like 10K used!!! I'd love to have one of those too, but i am in same ballpark as you. Hard to find perfection though. What I'm seeing that may be worth investigating at 2500 or less used:
Parasound A51
BelCanto evo6
Simaudio Aurora
Sunfire Theatre Grand (or cheaper Cinema Grand)

Just my two cents. Understand that I'm going completely off reviews and forums. No personal experience.

Hey, wanna buy a couple amps each and swap them, lol?