Christina Aguilera, 29
Like every great artist, Christina Aguilera is constantly reinventing herself. After starting out on Disney's The Mickey Mouse Club from 1993-1994, and maintaining a clean cut, wholesome image throughout her teen years with hit songs like songs like "Genie in a Bottle," "What a Girl Wants," and "Come On Over Baby," Aguilera changed her image with her second album, Stripped (2002), which was extremely raunchy. XTina's fans must've loved her evolution, because the album, which featured the hit song, "Beautiful," sold 330,000 copies in its first week alone! "This is such an honor and a dream come true," Xtina told Latina.com. "As a little girl I never imagined a star of my own. It really proves to me that all my hard work has paid off."