I just linked this thread to another similar request, so I'll link it here also with a few different comments.http://www.avsforum.com/avs-vb/showthread.php?t=790374
As to color and finish, you are right the flatter the finish the better. Secondly Black would be best and then any shade of neutral gray. If you can sell the wife on gray. If not I would next go for any of the darker colors. My preference would be from the tan side of the paint charts only because light striking the wall will be reflected off as the color of the wall. Skin tones are the first thing we notice when colors are pushed. If a face looks a little green we notice but if it looks slight raised by tan or brown etc we don't notice. If a tree or lake is altered in the image in that direction our minds just assume that's what color the tree etc is.
But many have used all the dark colors with great success.
Lights in the room and the darkness of the walls the closer you get to the screen have the greatest effect on PQ