37. GEORGE CLOONEY
The gravelly voice. The boyish smirk. The complete disregard for authority. After years of struggling in bit parts (The Facts of Life, Roseanne), Clooney's five charismatic seasons as tortured, womanizing pediatrician Doug Ross on ER — one of the most-watched shows on TV at the time — launched him to superstardom. And thanks to the second-season entry ''Hell and High Water,'' it's possible to identify the exact moment of takeoff: As Dr. Ross saved a boy from raging floodwaters, George Clooney, Movie Star was born.

Get This! ER, season 2