What's amazing, is that it is really all about the lights, not the color of the room. Go dark - period. Then add lighting. If you add sconces around the perimeter, then you get solid wall accent lighting that can make a different color really 'pop' on the wall while brightening the room a good deal, yet not at all impacting things when you really want the room dark.
See:
http://www.avintegrated.com/lighting.html
It's more about how lighting affects the screen, but you can see what a lot of well zoned lights in a front projection setup can do to highlight different sections of a room. Our room is medium grey (family room) which is about all I could get away with.