Done a house like that last week Participant and indeed thats how we painted it. However were doing another today by the same builder. In it, the windows are skylights and the ceiling curves down to the wall in some rooms. The client wants the ceiling white to just below the curve, hence the need for some very neat cutting in with the wall colour.
Our master bedroom is a dormer-style on one side and has a roof that slopes down almost to the floor. We're painting it as follows (pic's a bit random but whatever ):
There'll be a wardrobe there in about two weeks, but it's the same on the other side.
Ceiling.
Paint the entire room the same colour and be done with it.