Notable Mention:

Patti LaBelle

Dolly Parton (say what you want, her voice is timeless)

Marvin Gaye --> http://www.youtube.com/watch?v=s7eTOnNBwYU

Allison Krauss is the shit (And her band Union Station is the shit too) --> http://www.youtube.com/watch?v=YiyKwigIvkI