Drjohnrock

My list:

Richie Havens
John Sebastian
John Fogerty (played the fest as part of Creedence Clearwater Revival)
Jorma Kaukonen (played the fest as Jefferson Airplane's lead guitarist)
Joe Cocker
The Band (Robertson, Helm, Danko, Hudson and Manuel)
Steve Katz (played the fest as part of Blood, Sweat & Tears)
Graham Nash/David Crosby (played the fest as part of Crosby, Stills, Nash, with and without Young)
Canned Heat

And I should be albe to add one more musician to the list before the end of the year.