Let me throw my worthless US$.02 into this swiriling black hole of a thread that won't die, since I'm one of the thirty who voted surround sound to be a horseshit gimmick.
First, surround sound in and of itself has nothing to do with piracy. 2-channel DVD audio can be encoded with the same anti-piracy measures that 6-channel sound can. That is an argument that has nothing to do with "surround sound".
Second, there is a natural biological justification for stereo over mono; it takes advantage of the fact that we have two ears to create a natural sound field in which sounds can be localized and "put into a space". This creates not only an organic enjoyment that can't be had with mono, but also allows the instruments to mix in ways that "make sense" to our brains. Expanding the sound field to a surround sound at best only adds a limited amount to thees organic effects. The human ears *can* hear and localize sounds to our sides and behind us, but the main reason for 360 degree listening is for survival, not for entertainment. By nature, we want to face our source of entertainment, not put our backs to it.
Surround sound can be used in three ways:
1) to recreate a natural listening space through the addition of reverb and/or surounding audience sounds.
2) to create a natural 3D soundfield in which sounds can be originating from anywhere in the 360-degree range.
3) to provide an artificial 3D "canvas" on which the artist can "paint" aural images to new effect.
I'll get back to these three ideas shortly...
I am old enough to vividly remember the first time this debate raged, long before the days of DVD or even CD; the first time "surround sound" was marketed to the Great Unwashed, before many of you were even born. This was the '70s and the advent of Quadraphonic sound. Stripped to its essentials, quad surround was conceptually the same thing as today's 5.1, except without the separate center dialog and subwoofer channels.
Quadraphonic failed miserably. Many will say it was because of technical hurdles and competing formats. While those issues existed, they also exist with today's surround as well, so if that's what killed Quad, it could kill today's surround too.
But those aren't the real reasons Quad failed. To "quadraphiles", competing formats and technical hurdles were not an issue. My next door neighbor and I could playback QS, SQ and CD-4 quad formats all with no problem; it was just a matter of having the right equipment. Had quad had any staying power at all, the formats would have worked themselves out in the market place in much the same way VHS and Beta did a few years later. No, the problem was that quad sound itself had no staying power. Once the novely wore off, we discovered that quad sound not only
didn't add to the experience, but as often as not, it
detracted from it. And this is where we turn back to the thre points of surround listed above...
1) In the case of point one, surround sound does a great job of being able to recreate room ambience. The only problem is that almost nobody cares. While reverb from the rear and surrounding ambients might make a live concert recording more realistic and arguably pleasantly useful, it's use in studio recordings has at best a negligable positive effect on the listening experience.
2) A natural 3D soundfield can be nice when applied properly to a movie soundtrack. Hearing that bullet whiz by your ear from behind can scare the dickens out of you or hearing the cardinal singing in the tree to the left can add to the feel of a picnic in the park scene.
But how does it apply to a musical or even a theatrical performance? Contrary to what was posted earlier, one does not sit in the middle of an orchestra or a jazz combo, they sit in front of them. And as far as those of us who have sat in the middle of the music or been on stage with the band, I'm sure to a person that we can tell you that it sounds a whole lot better out in the audience than it does on stage. It's supposed to.
And even if we could make it sound good to be in the middle (which we technically could). mixing a band or orchestra to be somewhere other than the general direction the listener is facing winds up being more of a distraction than an enjoyable experience, because
that is how our ears and brains are wired. We are wired to treat direct (as opposed to reflected) sounds that originalte behind our field of vision as something to grab our attention, something to be wary of, not something to be enjoyed. The exception could be made for point 3...
3) Yes, having a 3D canvas on which to paint the aural sounds can be quite the experinece and can open up new horizons of creativity. Anybody who has heard quad vinyl pressings of early Hawkwind or Tangerine Dream can tell you what a trip that can be. I could even imagine real possibilities in effective surround mixing in some of street poetry that is today called hip hop.
But apply fancy surround engineering to the more "organic" music genres from classical to rock (rock is organic, you ask? Ok just give me that one, OK? This is a loooong post and I have to leave *some* things as postualtes

),
and the user will spend more time following the trajectories of the mix than the performance of the music. The listener will get tired of that real easy and will perfer not to be distracted from the performance. They'd prefer the stereo "performance" over the surround "production" now just as they did 30 years ago.
And I haven't even brought up the idea that surround sound is useless to those with iPods and the like.
This all boils down to - yes, I'll say it again - "it's the content, stupid." While stereo actually did add a
lot to the content (read: performance) and added to it in ways that made sense to us as human beings, the addition of surround adds at best only marginal quality to the (musical) content and is only really useful in a couple genres of music in which a sophisticated mix is actually part of the performance and not a detractor from it.
I see no reason why this is any different now than it was 30 years ago.
Fire away.
G.