my wife and I have really enjoyed discovering Florence and the Machine a few months ago.
I hope her being on the upcoming Twilight movie soundtrack doesn't overexpose her music
My comparisons to Bat for Lashes and Kate Bush are less around voice- and more around the visceral, visual, sensory nature of their compositions...where they are seen, heard and felt as a holistic piece and less a simple song
If you haven't seen Florence, check these:
http://www.youtube.com/watch?v=iWOyfLBYtuU
http://www.youtube.com/watch?v=7nxO-yPQesA
http://www.youtube.com/watch?v=TpLXQorSQe8