I would add Emmylou Harris, and possibly Bonnie Riatt.
Grace Slick, and if Allison Krause is in the mix, then Nanci Griffith should be too.
I agree with Emmylou....It should also include Lisa Gerrard.
Yes, definitely Emmylou Harris. Aretha and Emmylou and after that I kind of lose interest.
The girl who sang backup on the Stones’ Gimme Shelter deserves some kind of special mention.