In no particular order:
Aretha Franklin
Stevie Wonder
Lindsay Buckingham
Marvin Gaye
Jon Anderson
Brad Delp (I don't think of Boston as hard rock)
Lou Gramm
Stephen Stills
B.B. King
Ray Charles
Bonnie Raitt
Flora Purim
Elton John
Bill Withers
Chuck Negron from Three Dog Night
There's a zillion of 'em, but most of my favorite non-metal singers are pre-1980. Must mean I'm gettin' old...
