I've never really been that into female vocalists.....but the ones I did/do like are:
Linda Ronstadt
Stevie Nicks
Carole King
Elkie Brooks
Dusty Springfield
eta
I forgot Buffy Sainte-Marie! I saw Soldier Blue in about 1970 (I think) and this song really got to me
[ame]http://www.youtube.com/watch?v=sIdYs9vo81U[/ame]
i'm sure there are others that have been lost....along with my memory!