I've been a fan of Ozzy Osbourne ever since my uncle got me hooked around age 10. The old dude might need a teleprompter now to get him through his songs but from what I've heard he still puts on good show.
Mick Jagger. I realize Mrs. C already named him, but he stands alone. He has always been the major contender of wise, old and healthy. When does this dude ever get sick, bless his heart? May he stay forever young.