Paul McCartney. He was a good songwriter and walrus.
Keef... oh wait, he just
looks dead. (I see he was already mentioned, laff).
Janis Joplin, I think she would have just gotten better and better.
I wonder what more great music we would have from Hank Williams and Patsy Cline.
Robert Johnson... dead at 27. Incredible legacy.
Gram Parsons.
..and of course Duane Allman and Berry Oakley.
J