I think I’m about 6 months late on this thread but the female vocalists/bands I really like are:
Come / Thalia Zedlek
Tara Jane O’Neil
Mary Lou Lord
Jodi from the Secret Stars
and if you count some of the Versus songs and My Bloody Valentine whispers.
Like a few other people have said, I really dont find myself listening to bands with girls singing much. It’s nothing intentional, and based on the list above I have quite a few CDs of girl-fronted bands, but I just dont find myself going out of my way to listen to them. Can’t explain it.