8. Paul Bettany
You've Heard Him In: Iron Man (2008) Like a lot of the actors on this list, Paul Bettany has gotten quite a bit of success as a voice actor; his most prominent role to date is, surely, the voice of Tony Stark's AI, J.A.R.V.I.S., in all three Iron Man films and The Avengers. He's appeared in other blockbusters, too, including A Knight's Tale, Master and Commander: The Far Side of the World, and The Da Vinci Code; the fact that, despite those appearances, nobody seems to know his name, is exactly the issue. He's a wily and diverse actor, with something of an intellectual mien and cold, blue eyes; he's portrayed everything from Geoffrey Chaucer to an insane murderer.
The Role He Needs: Something like A Beautiful Mind, except better. Bettany carries a kind of quiet tragedy around with him that's rarely been tapped; some kind of mid-20th-century tragic academic would be an extraordinary opportunity. I'd even go so far as to suggest a biopic about Alan Turing, the doomed mathematician credited with inventing the personal computer in the 1950s and helping win World War II with his codes who was, later, sentenced to chemical castration by the British government for his homosexuality and ended up killing himself, if such a biopic weren't already in the works with Benedict Cumberbatch, set to be released later this year.