I don't really have a sewing room yet, but when I do get one, I really want a large drawer for putting all the components of a project, without having to fold the heck out of it.
I'd also like a closet of sorts, because it seems like I always have a quilt top or some interfacing that I'd rather hang than fold.
A large ironing board, a large design wall, a sturdy cutting table at a height that's right for ME, oh yeah, and a long arm machine! I'd want all those.