I love female vocalists but havent heard any in "metal" that thrill me. Ann Wilson (of Heart) and Benetar always struck a cord for me. About the only two in rock that worked for me, I hated Blondie and Joan Jet. The woman that sang Mary on Queensryche MC is awesome . Otherwise they are the best for mellow music and typically dont have what it takes for hard driven stuff.
Joplin ruled !