Kelly Clarkson won the inaugural season of American Idol, spring-boarding to a fantastic career in which she has released four studio albums to worldwide sales of more than 20 million units sold. She was named the show’s all-time most successful competitor by Billboard magazine in 2010.

Soulful Ruben Studdard edged out Clay Aiken to win the show’s second season crown, and received a 2004 Grammy nomination, but his finances have made for quite the sad song. Despite having accounted for more than $2.2 million in album sales, his credit was so bad at one point that he could not get financed for a house. In 2006, Studdard won $2 million in his lawsuit against his ex-manager for misappropriating the singer’s money and credit cards.

Fantasia Barrino has had huge success since beating Diana DeGarmo and Jennifer Hudson for the show’s third season crown in 2004, making her mark on both the charts and on Broadway, where she was cast in The Color Purple musical. She’s released two hot-selling albums which have garnered her eight Grammy nominations. She even starred in a Lifetime movie about her own life. Her third album is slated to hit shelves summer 2010.

Carrie Underwood parlayed her win on the fourth American Idol season into a career as a country music superstar, having sold millions of albums and winning seven Grammy awards on 11 nominations. Another incredible feat: She is the first ever female artist to win back-to-back Academy of Country Music Awards for Entertainer of the Year in both 2009 and 2010.

Taylor Hicks went from obscurity to fame and back again: the grey-haired crooner won the fifth season crown on American Idol, but could not maintain his momentum in the music business to move onto bigger and better things. He’s currently making ends meet performing in a touring production of Grease, playing the role of Teen Angel.

David Cook won the show’s 2008 competition and shot up the charts with his self-titled album thereafter. He’s been a hit with the younger generation, having garnered Teen Choice Award nominations in 2008 and 2009.

Kris Allen emerged the winner of the 2009 competition despite his underdog status to heavily-hyped Adam Lambert. The handsome Arkansas native’s first two singles, No Boundaries and Heartless, both made the Top 20 of the Billboard Hot 100 upon their releases.