I don't think it's so much color accuracy but more room appearance. I have been in HTs with dark flat paint and in them with lighter glossy type paint and in the lighter ones the whole room lights up when the projector is on, which destroys part of the experience.
In a proper room the screen becomes the only thing that can be seen. I must admit that is not the way it was in my last HT (wife refused dark grey walls) but I was not happy with it - NEXT time I'm putting my foot down http://www.avsforum.com/ubb/wink.gif
Lex MC1/Sunfire CG/Hales Rev3's x3/M&K SS150 tripoles/Quadscan/Plus UP1100/Homemade screen