I have a general question about surround sound.

Actually, at a live concert, the sound comes from all around your head through reflections. The directional cues that you relate to come from the front only. The richness of the acoustic experience relies on accurate rendition of stage depth and reflections in the listening environment, usually a larger one than a home. Incredible expense and art have gone into designing concert halls to provide the best acoustics. Two channels can only present a window into the direct sound with perhaps some stage depth. If you use multichannel to deliver the appropriate sonic environment, than yes, it is superior to two channel. Multichannel has the benefit of stabilizing bass and midrange and reducing summing and cancelling nodes, making these tones much more rich and believable.
It is impossible for two channels in front alone to present a complete acoustic experience and this has been demonstrated through psychoacoustic research, although some audiophiles cling to the notion that somehow two channels are always the best.

The thing is, when you get your 2-channel right, you do feel enveloped by the music - in the correct way. That is up to us to discover the tweaks (room treatments etc) that get us there. With multi-channel, you are at the mercy of the mixing engineers who want to "Whizz-Bang" listeners with things like tambourines in the rear channels.

This is like one of those questions about "the best" or "who is right" it's all Apples and Oranges to me. I've kept my stereo system in the ex-family room and placed my surround in the living room with the TV.

Multi-channel sacd's can sound phenominal (Roxy Music "Avalon") or horrible (The Police - any). The classic's have the same problem. I would never give up my multi version of Orff but there are many others where the ambience is mixed ridiculously low.

Yes, I listen to "Dark Side ..." on the stereo system BUT I also enjoy the quad type mix on the surround every now and then.

I detect the fundamental knee-jerk reaction to anything but two channel stereo. The ambiance of the recording venue is not very well reproduced by two channel. A number of audible cues are present on stereo recordings, but to reproduce this "other dimension" of sound, added channels are required. How many and what to pump through them is another issue, but the fact remains that to come out with the two statements that music only comes from the front of the hall and that we only have two ears so why more than two speakers is simply wrong.

Jkphoto wrote: "The thing is, when you get your 2-channel right, you do feel enveloped by the music - in the correct way."

It may be satisfying but it can never be correct. The reflections generated by your listening room are not anything like the reflections/ambience of the performance site.