There are so many great ones, but I think I'd have to go with Ella Fitzgerald.
I like Hayley Williams of Paramore. That's one of my favorite bands and her voice is awesome :)
Varies all the time?
Stevie Nix and Mariah Carey.
John Cougar Mellencamp.
Hands down Sarah McLaughlin.
So many. Unfair question. If I had to pick a desserted island answer it would be Damien Rice.
It's a tie between Eddie Vedder and Layne Staley.
Stevie nicks or amy lee