He has an amazing and intimate knowledge of twentieth century U.S. history that can sometimes be scary - especially as, for some fair bit of it, he was there, front and center. His numerous insider stories give both proof and color to his personal and professional influence over these events, and can be quite enlightening with regard to the foreign policy process.
Some of the classes that he's been known to teach include
He's a very friendly person, who's always willing to grant a term paper extension should one be needed.
He has lots of great stories to tell: the one about the tiger pit in Guatemala, about when he didn't go to Disneyland with Nikita Khrushchev, how he nearly got on Nixon's bad side because of modern art, the various times he was almost shot... just to start. Make sure to take a class from him at some point!
Do be warned that Davis classes demand a long attention span, and often tend toward lectures/monologues rather than discussion. They may not be everyone's idea of fun, though most students seem to enjoy them.
Sowing wild oats has become more and more hazardous these days.
The state would wither away in one great crashing wither.