First known as the winner of American Idol's debut season, Kelly Clarkson is an all-around entertainer with a powerhouse voice and plenty of charm. Her warm, multi-octave vocals are equally at home in pop, rock, and country, all of which she excelled at on the show. Clarkson's fame was instant -- her debut "Before Your Love/A Moment Like This" was 2002's best-selling single in the U.S. -- but she defined her career on her own terms almost as quickly. She pivoted from the mainstream pop of 2003's Thankful with the following year's Breakaway, which spanned the anthemic, rock-tinged smash "Since U Been Gone" to the power balladry of "Because of You."