If it is a new room, and WAF is not the determining factor, why not try it several ways and see what you think. One setup that I have heard, and which is rarely if ever mentioned is a diagonal arangement, where the speakers are not against any one wall. It sure confuses those pesky room modes.
HELP Which wall of new room to put system on?
I'm probably moving my system into a new room. The room is about 15' wide x 20' long. I will put the system on one of the 15' walls. The room height is 8' except that one wall only goes to 5'4" and begins a gradual slant up to 8'. I would like to get everyone's advice about whether I should put the main system / front speakers on the wall with the slant or on the wall that goes straight up to 8' tall. I'm hoping that, in some way, this will be a sonic advantage. I'm just not sure if the slant should be behind the main front speakers or on the other end of the room from them. By the way, the main front speakers will probably sit about 5' off the wall.