Simon Cowell

Biography: A sharp-tongued British personality whose cutting but often hilariously honest comments have dashed the dreams of countless aspiring singers, Cowell was a successful music producer before being tapped in 2001 to be a judge for Pop Idol, the British reality competition that was the basis for American Idol. Since then, Cowell has practically made a career out of being disliked, as his outrageous put-downs and tempestuous relationships with host Ryan Seacrest and former judge Paula Abdul have been a large part of Idol's mass appeal. Throughout his time on Idol, Cowell also launched several reality-competition series, including American Inventor, America's Got Talent and Celebrity Duets, as well as the short-lived matchmaking series Cupid. In 2010, Cowell announced he was leaving Idol in order launch a U.S. version of the popular British singing competition The X Factor, on which he's served as a judge since 2006.