There was a thread about Great female rock voices
so I won't repeat what I said there.
Some great non rock female vocalists ...
Nina Simone - timbre and phrasing
Dagmar Krause (Henry Cow) - amazing expressiveness and pitching impossible intervals with ease
Joni Mitchell - lovely tone, great range and with intelligence
Dusty Springfield - timbre from heaven
Diana Krall - lovely husky jazz voice
Roberta Flack - smooth as silk
Shelley Bassey - pure power and style
Ella - the complete jazz package, great scatter
Anastacia - fabulous throaty tone
Patti Labelle - fun-kee!