The lovely Casady sisters -- the classically trained, operatic Sierra and the intuitive, Wu-Tang-loving Bianca -- provide a fascinating case study in competing and complementary aesthetics and talents. Since surfacing in 2004 with their first album, La Maison de mon Reve, famously recorded in a Paris coldwater flat, the duo has become a fulcrum of New York's vibrant music scene. They're often lumped with the independent folk renaissance, due mostly to the fragillity of their compositions and their friendship with Devendra Banhart, but the Casadysreally occupy a musical world all their own, one in which stuttering beats live alongside plucked harps, piano figures collide with decaying loops created from toy instruments, and Bianca's sauntering, scratchy streetwise menace counterbalances Sierra's refined skyscraping pathos. The duo's second album, Noah's Ark, released in September 2005, was darker, stranger, and better than the first. CocoRosie's self-conscious bohemianism and relentless experimentalism has polarized audiences in the past, but spend enough time in their world and you won't want to leave.