Michael J. Fox deserves a lot more attention. Even in the face of Parkinson's Disease, he still keeps moving forward, and being positive.

(All that aside -- Stewart makes a good point. How in the hell do he still look so young?)

It's not unlike Jason Becker, who continues to make music (indeed, who continues to wake up day after day) well past the life expectancy that doctors gave him. He suffers from ALS (Lou Gehrig's) and refuses to let it affect him any more than it has to. There's a nice news piece online that documents a lot of this.