I"m game for more channels but the effects have to be subtle for me.
Subtle creates that surround effect w/o making it feel overpowering from all sides.
There's nothing like listening to a concert cd and be able to hear the echoes off the side walls and in behind. It really adds to a realistic effect in the way we perceive sound, never just from one direction.

"Those who preach the myths of audio are ignorant of truth."