On the idea of people who can play a lot of different roles and do them well I would have to say that character actors such as Gary Oldman, Robert de Niro take the prize. If you're looking for people who rise, or sink to the level of the movie, then I would say that Christopher Lee takes the prize.
Mr. Lee's acting resume is impressive with movies that you can say "Damn, that's one great movie." (Say, the Horror of Dracula, the Wickerman, The Lord of the Rings)
, or "Meh, that's kind of average" (Willy Wonka and the Chocolate Factory, The Mummy, Return to Witch Mountain), and finally -
"Man, did they have nude pictures of you with some kind of farm animal?" (Howling II, Taste the Blood of Dracula)