"Complicated"

Now that Britney wannabes are out of vogue, labels are falling all over themselves for ''substantive'' young female singers like Michelle Branch. Even with a full band, Canadian skater-girl Lavigne doesn't rock harder than her competition; her debut single is pretty mainstream. That's okay. ''Complicated,'' a melodic midtempo tune about the frustrations of being 17, is flawless radio-pop.