Sweet and vicious in equal measure, Lily Allen's early demos and debut LP, Alright, Still, set the stage for modern pop's most celebrated Trojan horses. M.I.A.'s weaponized mash-up pop channels Allen's aptitude for barbed-wire lyricism, and in Charli XCX's party-till-your-eyes-bleed excess you'll hear Allen's gift for loaded, soaring hooks.