For a long time, George Clooney was just another handsome rake who turned up in guest shots on TV. But his five seasons on 'ER' changed all that. Not only did his role as likable cad Dr. Doug Ross make him a household name, but it also made feature film casting directors reassess him as leading man material.

To put it mildly, Clooney's scored big in that kind of role, and has used his good looks, native intelligence, good humor and smoldering stare to manage a dual career as a serious dramatic actor and a good-time comedic lead. Clooney is unafraid to tackle films that ask serious questions about the world of politics and power. He also knows how to pick vehicles that will sell tons of popcorn.

With the release of the assassination thriller 'The American,' here's betting he does both -- just as he did in varying degrees with these, his 10 best films:

10. From Dusk Till Dawn (1996)
With 'ER' a ratings winner, Clooney caught the eye of Robert Rodriguez, who directed this horror flick written by Quentin Tarantino. Clooney plays Seth Gecko, a lowlife who's on the lam after a bank robbery, and stops off in a strip club that just happens to be full of vampires. (Dontcha hate that?) Since this is a horror flick, the rules dictate that Clooney eradicate as many of them as possible, which he does in graphic, bloody style (a.k.a. the Tarantino Rules). A tongue-in-cheek thriller that helped further solidify Clooney's devil-may-care screen persona.