icefrk13,
I had some diagrams from one company that had described a setup for speakers in a room.
It wasn't quite an equilateral triangle, had a bit of simple math to it, but in any event, do not limit yourself to having to keep to such a strict rule.
I've often found that as long as there is some symmetry between your seating position, left and right speakers and equidistance between them if you have a centre channel, that stereo sound will work quite nicely.
If you are interesed in seeing the setup diagram that i mentioned, i will try to dig it out of the archives for your perusal.
