Personally I think EMT is BEAUTIFUL!

I'd use EMT for the whole job (I feel any exposed NM is subject to physical damage--obviously a higher standard than the NEC), but I see NM used in the county. Usually it's run on the joists similar to the way it would be run in a basement ceiling. However, when you mention surface wiring on top of sheetrock I think 334.15(B) comes into play.

Dave