7. Patrick Troughton (The Second Doctor, 1966-1969)

As just the second actor to play the Doctor, Patrick Troughton created a remarkable legacy for himself and the show. He broke from William Hartwell's stern characterization for a much more effervescent and emotionally rounded take on the Doctor. He also proved that fans would jump aboard the show's regeneration plot twist that allowed the Doctor to be played by multiple actors. Later producers and directors credited him for creating the mold that would influence all future Doctors.