Lots of great choices already. I don't disagree with any here, though I am not sure about Grace Slick. I got tired of her in the late '80s. Etta, Ann Wilson, Nina Persson are some of my favorites from the above list. 'Retha I like but in measure, same with Ella.
Some others:
Brandi Carlile - That girl can rock, can croon, can belt it out, and can sadly whisper. She is great live.
Nathalie Merchant (I like that sultry coffee house thing)
Kim Deal (The Breeders) good stuff, love that punky rock snarl.
Bonnie Raitt - has that weary blues thing down and can sure pull a heart string
I could keep thinking of many others if I kept going. I love a good female voice. One sub-genre I always enjoyed was the voice of the 80's girl band groups. I don't even know their names mostly. Of course there is Belinda Carlile, but also the girl from "The Waitresses", Nena, "Bow Wow Wow", Romeo Void, Blondie, (ok 70s but whatever) etc. Heck, I was in my late teens and they were like singing to me from the TV. LOL! OK, not the "favorite" female vocalist of all time, but these women deserve to be remembered darn it.
EDIT: I forgot to mention Marian Call. She is my cousin's daughter, but she is dang good. Stanford Chorale, and degree in composition and vocal performance. Huge range, really cool note choice due to all that training, building some good sultry heart and soul as she adds years to her young life. I bet she will be really good.
Steve Thompson
Sun Valley, Idaho
Guitars: Fender 60th Anniversary Std. Strat, Squier CVC Tele Hagstrom Viking Semi-hollow, Joshua beach guitar, Martin SPD-16TR Dreadnought
Amphs: Peavey Classic 30, '61 Fender Concert
Effects and such: Boss: DS-1, CE-5, NS-2 and RC20XL looper, Digitech Bad Monkey, Korg AX1G Multi-effects, Berhinger: TU100 tuner, PB100 Clean Boost, Line 6 Toneport UX2, Electro Harmonix Little Big Muff Pi, DuhVoodooMan's Rabid Rodent Rat Clone, Zonkin Yellow Screamer Mk. II, MXR Carbon Copy Delay
love is the answer, at least for most of the questions in my heart. . .
- j. johnson