I tried it once just for kicks. The system sounded fine in that configuration but I could not overcome the visual stigma of staring into a corner, just too weird.
Diagonal setup of system...
The other day I had to move my system to clean around the area. I carefully marked where everything was before so that I could put it back the way it was. In order to get to some places on the floor, I had to move the entire system over to a corner. I decided to hook it up to listen to music while I cleaned the area. To my surprise, my system sounded better than it did with a conventional setup, side to side. The system was setup diagonally, sub in the middle, in the corner and mains on each wall. Any reason for this? I am thinking of keeping it this way.