I've actually thought about this alot for my next sewing room. Currently my sewing room is a bright yellow. This is because it's in the basement with no windows. If I had a room with windows, as much as I hate to say it, I would probably pick a snow white. The color of my space would definitely influence the quilts I made.

I usually hate white walls, but this is a time when it might be warrented. I would also consider a very light dove grey.