Avril Lavigne first appeared as a spunky teenager crafting surprisingly sharp alternative pop-rock that sounded great on the radio and fit very well in your CaseLogic (right between that Alanis Morissette stuff you'd gotten a little sick of and the Fiona Apple album you held so dear). She was one of many tender-aged smart-popsters who came up in the early 2000s, a group that included Michelle Branch, Norah Jones and Vanessa Carlton. She first hit with the acousti-groove of "Complicated," but it was the charging alt-rock of second single "Sk8er Boi" that showcased the range of Lavigne's impressive talents. She released her second album, Under My Skin, in 2004, expanding upon her catalogue of sharp, smart radio tunes and leaving the teenager thing behind. She married Sum 41's Deryck Whibley in 2006 in a storybook wedding wherein Lavigne shocked Hot Topic shoppers and sk8er kids everywhere by rocking the big, white dress, then split up with him four years later. Both events had a major impact on her sound: 2007's The Best Damn Thing collected more mature ballads and some of her poppiest material yet, while 2011's Goodbye Lullaby found Avril both processing her divorce with brokenhearted confessionals and reviving the brat-pop of her single-girl days.