one 7 channel amp or seperate 2 channel amps?

I prefer using multiple amps. I use one amp to power the main speakers which I use for movies and 2 channel listening. I have a stereo surround amp in the back of the room, so I use long shielded RCAs and shorter speaker wires. I also use a third amp to power two center channel speakers, one on each side of the TV monitor.
Sonny

I have been all over this same issue in the past 3 years - 2 amps, 1 amp and 4 amps to run 5 channels! This is not an easy decision....

To run a Talon "Raven's Nest" 5.1 setup, I started with a 2-channel Pass Labs X-250 and 3-channel X-3. Though the sonic synergy with the Talons wasn't really there, the dynamics WERE terrific.

Next, and like Mr. Pixel above, I then employed a Titan running all 5 channels for the same speakers, and it was really great. It matched the Talons' sonic characteristics perfectly - smooth and natural, it's amazingly cool-running (efficient), provided a very deep image/stage, never sounded stressed even in *HEAVY* 5.1 use and was just plain easy to live with. I didn't realize just how good this amp was until I sold it...

Then, in my infinite wisdom, I surmised that 3 monoblocks for L/C/R and another running stereo for the rears *MUST* be better for dynamics and overall sonics then one good 5-chnl amp. To be honest however, I really gained nothing decernable except system complication - just more expensive cables, more rack space taken up, etc. And these mono amps are no slouch (Electrocompaniet AW220's).

Having said all this, I am now going to try to get back to a simpler middle-ground. I have a 2-channel Sim W-5 LE on order right now, intending to replace a pair of the monos to drive the front channels and use exclusively for 2-channel operation. If this works out well, I may jump on a 3-channel Titan to drive the rest of the setup (center & rears).

Keep in mind that ALL of my equipment has always run from ONE 20-amp AC outlet, feeding a single B-P-T 3.5 Signature line conditioner to drive all the stuff - including all the amps. I know this is not optimal, and could certainly effect the results here, but I can't add dedicated circuits to my environment right now. At least the power conditions have remained identical throughout these changes in amps.

I don't know if this will help in your decision, but I CAN tell you that the Titan has never sounded like an amp "compromised" by running all 5 channels in my system.

..... But YMMV .....
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Why not biamp? the Titan sounds like a nice unit. Run four amps of it to the speakers (you'll need to biwire them). that should knock your socks off, and likely you'll feel no need to purchase a new amp for main speakers. The only drawback, then you'll be looking for an amp for two of your surround channels.
Some suggest you must match all amps in your system. If that's not critical to you, then you can experiment with many options for surround amps, and can possibly purchase one of less cost than a dedicated two channel for mains.
Just a thought. Purists might frown on this suggestion, but I'm brainstorming. I have biamped, and found it to reveal a whole new level of listening enjoyment.