Two-channel is inferior to multi-channel, no?

"I know we're not talking cheap home theater but that is where center channel helps the most. In my system imaging is close to perfect and sweet spot is wide enough for me."

I beg to differ. If you haven't heard it for yourself, you can't attest to it. The center channels holds more than what your implied limitations are. If you don't know then you don't know. As for imaging, if close to perfect and wide enough are criteria you're willing to settle for, then welcome to the holy grail of audio.

Bose Acoustimas...used as a comparison...well, I'll just leave that alone altogether.

"There are people who believe that amount of gear speaks of the quality and keep buying multichannel amps, speakers, equalizers and others. If objective is to have special effects for the movies it is different story but for music alone 2 channel system with better speakers and amplifier will deliver more thrilling sound."

Never mentioned anything about amount of gear and its relation to MC. More specifically, I never mentioned the common novice audiophile misconception. Special effects, music alone, 2 channel does it better....its all regurgitated postings. Far from original in content and a bit off topic.

Lastly, who says you can't get the best of your 100w amp in the 200w version? We're not discussing application needs or which amp is better, we're talking how the center channel can improve your soundstage.

"better imaging and better midrange 2 channel system instead of fixing worse system with third channel IMHO."

Two words: User Error. If you don't know how to incorporate a center channel, don't blame it. Besides, if your building that bad of a system, one should be doing more reading and learning here on audiogon.

If the music is mastered in proper and thoughtful multi-channel sound than it will be a superb sound reproduction vehicle. Taking your stereo Redbook CD or a vinyl LP and turning on one of your processor's DSP, multi-channel Codecs may not give you the audio results you like. But some do a pretty good job. My Onkyo TX-SR806 with THX Music Cinema employed does make regular stereo recordings sound, meh pretty good. But take a hi rez digital disc properly mixed into multi-channel sound such as those Blu-ray audio discs offered by AIX Records, any Oppo BDP-83(se) user has a sampler disc in and WOW, OH WOW, OH WOW can it sound credible and lifelike.

I have mixed feelings about this... I have been using a HT based system for about 6 years - B&K Ref 50, BAT & Sherbourn amps, Dynaudio Countours for 7 channels, Rel Studio connected both high level & line level in a Rives Audio designed room optimized 50/50 for HT and stereo listening. Recently I bought a BAT 31SE here on Agon. Hooked up my B&K system thru the BAT in HT bypass mode, but also connected my Pioneer BDP-09FD directly to the BAT. I was shocked at how wonerful some of these DVDs & Blu-rays sound in 2 Ch, admittedly better than the 7.1 set up - and it was quite easy to do A-B testing by switching inputs on the BAT. Points of reference here were Roger Waters 'In the Flesh', Killers 'Live at Royal Albert Hall', U2 'Vertigo in Chicago', G3 (Satriani, Johnson, Vai). Perhaps some other media may sound better in 7.1, but musically, the stereo listening with these aforementioned DVDs just oozes with smoothness, clarity, weight, etc.

More thoughts,

If there is only one listener sitting inside the stereo sweet spot, a stereo recorded album, (CD, LP, Tape etc.) then likely stereo is going to give you the best compromise in sound quality via recorded music. If you have multiple listeners, I find after much auditioning/testing of my system that engaging a DSP such as Dolby Digital Music, DTS Music or if you have the THX choices to each above will give a better compromise presentation for all listeners in room. I find that even DSP Stereo with Audessy eq. sounds better for all if you have multiple listeners in room.

If the disc was properly engineered in multichannel surround then in a properly setup home system it will sound superior to the stereo alternative if said disc has both to for you to choose from.

"The obvious reason, I am thinking, it is that two channels are less representative of infinity (live music) than 3, 5 or 7, etc."

7 channels of louder volume doesn't equate to better volume. I believe so often in this hobby one equates different as necessarily better. Of course, if I've invested into mass amounts of gear I'm of course having to justify that purchase so in my mind I'm convincing myself this has to be better. I'd leave better out of it. It's just different sound. A decent 2 channel rig will always sound as good as a multichannel one, but in the end what matters most is what satisfies you the listener...or the short version is, whatever floats your boat.