Britney Spears [1] proved once and for all that she's the queen of pop at the Billboard Music Awards [2] on Sunday. She's the third-ever winner of the Millenium Award, and she opened the show with a medley of her greatest hits, including "Work, B*tch," "I'm a Slave 4 U," "Womanizer," and "Toxic." She even gave Crossroads fans (myself included) a shout-out by singing the chorus of Joan Jett's "I Love Rock 'n' Roll." Check it out!