This was fun to think about. (I'm listing them with one of my favorite songs of theirs.) I tried to do this quickly like the instructions said. So in some cases I may have not listed my favorite song that features their vocals, and I probably left someone really important off the list who should take a weaker choice's spot (I'm looking at you David Lee Roth). And this is in no particular order:
1. Elvis Presley - Burnin' Love
2. Freddy Mercury - Somebody to Love
3. Robert Plant - Baby Come on Home
4. Otis Redding - Try a Little Tenderness
5. David Lee Roth - Running with the Devil
6. Whitney Houston - Greatest Love of All
7. Al Green - Let's Stay Together
8. Michael Jackson - I Want You Back
9. Van Morrison - Sweet Thing
10. Geoff Tate - Silent Lucidity
11. Jeff Buckley - Hallelujah
12. John Lennon - Twist and Shout
13. Aretha Franklin - Natural Woman
14. Ronnie James Dio - Rainbow in the Dark
15. Janis Joplin - Mercedes Benz