The best rock bands I've heard in past couple of years both have female singers. The Pretty Reckless album is great even though it never came out in the US. Because the lead singer is only 17 and is always doing "outrageous" things the band was dismissed as a joke. Problem is, the album was really good. Best rock album I've heard since the Strokes.
The second group is Paramore, whose second album is great from start to finish.