Typical 5.1 surround sound requires 6 speakers. Most non-audio/video-phile friends I talk with think that having 6 speakers in the typical family room is quite a stretch, and some are resistant to even having that many speakers. I have a very large room (18 ft by 18 ft with 9 ft ceiling) and the 6 speaker setup fills it out just fine - with plenty of good sound localization.

Do the manufacturers pushing more speaker formats have an idea of what (small?) portion of the public wlll buy these 7- and 8-speaker formats? what's next -- a speaker in the center of the room on the ceiling? 2 speakers in the ceiling? a speaker under the chair for that rumble below? a speaker every 6 inches?

Enough already -- this is way, way, way past the point of diminishing marginal improvement.