I agree on the Pioneer that you *may* not need to upgrade to something else. Give things a try first before spending more money. The receiver you have, while not "top of the line" is still very popular.
I agree also that a diagonal placement will really mess with the audio. I used to have a room that things were far from idea with angled walls, and odd shapes (sort of like what you would have) and my sound quality suffered. I am building V4.0 of my home theater (should have walls framed up this week yet) and I am able to build it the way that I want.
The VP180 will serve you well. I can't wait to get mine. I am also added 2 more QS8s for my 7.1 setup. Should be real nice.
