Rose, Amy, and Rory are three companions I never need to see again! I loved them all in their own special way, but they had their runs and its time to move on. I'd like to see Donna again just to make sure she's doing well (not a speaking role, just Matt watching her from a distant). Martha I wouldn't mind seeing again as head of UNIT or something. Capt Jack, only if he's sporting a bow and arrow.