"As far as expecting guests to hear what you are hearing, that will never be the case for any guest sitting off-axis whether you use a single center channel speaker or dual centers..."

Alan,

wouldn't the Audyssey MultEQ take care of this problem. I don't know how the cheaper version of this works (the one that only has two microphone placements), but people seem to like the one Offered in some of the midpriced Denon's (they have 8 microphone placements). Well, some say that it may make things sound a little artificial. But I had my eye on this one: http://www.audioholics.com/reviews/acoustics/audyssey-multeq-pro-sound-equalizer
With the Multeq pro it just enlarges the sweet spot so that everyone is hearing that sound no matter what seat they are in, but without sounding overly processed or artificial.

Many people around here are talking about how they want to buy a new and expensive amp but they don't even worry about how the room is affecting the sound. The Audyssey MultEQ is supposed to make every seat sound like the sweet spot as long as the room isn't too far off of ideal. I bet you'll notice much more of a difference from the MultEQ than you would a new expensive amp. I'm planning on running the MultEQ Pro between an Outlaw pre-amp and Outlaw amp. But, it will be a little while before I can get the money together, since that is about $4,000 total.

- Nick