Well darker ceiling gives best picture quality and image performance so whatever you do I think if you make the ceiling dark (black obviously the best) it will be good in terms of your cinema experience. My suggestion was coming from that angle.
Black ceilings (fabric) over acoustical treatments will also be best for not just picture but for sound too. Obviously color doesn't effect the sound, but the treatment does. I was just thinking combine the best of both words. Turning it into a star ceiling is one way to keep it from being plain. You can turn it off too. But if that's not your thing I'd do something with geometry ... Diamond's or circles or ovals could be cool.
"Too much is almost enough. Anything in life worth doing is worth overdoing. Moderation is for cowards."