These are favorites....note that there is always crosspolination between genres meaning that rock is pop is blues is RnB is....
The Men
Opera- George London, Dietrich Fischer-Dieskau, Luciano Pavarotti (1970's)
Pop/Rock- Sting, Paul McCartney, Donald Fagen, Paul Rogers, Freddie Mercury, Roy Orbison
R/B- Marvin Gaye, Stevie Wonder, Sam Cooke, Otis Redding
Jazz- Nat King Cole (also a KILLER pianist), Jimmy Scott,
Blues- Mighty Sam McClain, BB King,
The Women:
Opera- Leontyne Price, Kirsten Flagstad, Christina Ludwig, Elisabeth Schwarzkopf
Pop/Rock- Chrissie Hynde, Julia Fordham,
R/B- Beyonce, Anita Baker, Patti LaBelle, Aretha Franklin, Roberta Flack
Jazz- Sarah Vaughan, Ella Fitzgerald, Billie Holiday, Patti Cathcart,
Blues- Odetta, Etta James