Of the bands I listed as my faves, there are quite a few females:
Ida – Elizabeth Littleton. She can sing circles around most people. She’s also a great lyricist as well as plays moving folk-rock and uses other instruments like violin, accordion, etc. in funky ways to create great sounds.
Yo La Tengo – Georgia. Her voice IS Yo La Tengo. "You Can Have it All," is a good example of this.
Secret Stars – Jodi V.B. with Geoff Farina. Her vocals are great and she writes great songs.
Can’t say much about Kim Gordon, Madonna (who I have loved in the past but I must admit, didn’t have talent until she worked on it and then all of a sudden got some unspecified accent), Janis, or Courtney L. But, L7 is fun if anything else. And I do love the motown and soul ladies, e.g., Aretha, Supremes, etc.