[Drumroll]
10. Can’t tell Cheney jokes anymore without angina pains
9. Interns can no longer find it
8. Last good idea was Calvert DeForest
7. Never, ever, ever, ever, ever getting the Tonight Show
6. The ‘80s were a long-ass time ago, bro
5. Syphilis
4. Wants to devote few remaining years to stalking Palin
3. Stupid Grandpa Tricks
2. Outlasted Leno, so hey, WTF
1. Dude is old as $#!+
(Thanks to Rick Evans for the assist)