@OP: I would recommend you go a little longer first before going wider so i second the 85mm.
@The Artist: No, the 50mm isnt long enough on APSC sensors. It's about how it looks, not just about getting close enough to fill the persons face in the frame. If you shoot with a longer lens from a longer distance, the compression and look are much more flattering. That's the reason you'll sometimes see fashion photographers use 135mm and even longer in their portraits or headshots when they couldve just used an 85mm and moved closer.