Unfortunately, I never got to see Chamberlain or Russell play. From what I've heard, Wilt was the king of offensive big men, and Russell dominated the defensive side.
It also would have been nice to have seen Alcindor play when he was young. Sadly, I never saw him until he was "Kareem", an old, balding guy who was probably just a shell of his former self.
Having said that, I think the two most complete centers I ever saw were Hakeem Olajuwon and Shaquille O'Neal. Shaq was more dominant, just because of his incredible size, but if I had to choose one, I think I'd go with Olajuwon. He was so good on defense, and his footwork on offense is second to none.