I am double posting almost twelve hours later.

I forgot to mention CocoRosie! Bianca and Sierra definitely have some of the most unusual and strange female voices I've ever heard in my life. One of the sisters reminds me of Joanna Newsom, one's voice is just lovely - CocoRosie - Lemonade, CocoRosie - Armageddon. This song is coupled with them and Antony Hegarty from Antony and the Johnsons, who has an equally strange-sounding voice and I think it works so well. CocoRosie ft. Antony Hegarty - Beautiful Boyz

Also, I accidentally left out Coheed and Cambria. No one can deny this dude has a crazy unusual voice. Coheed and Cambra - A Favor House Atlantic