My favorite is any non-AA pair that makes a set on the flop against an AA that didn't bet enough pre-flop to keep me out of the hand.
I really love people who limp in preflop w/ AA, then decide to start betting on a flop that made me two pair or a set.
If you do, what is your favorite hand? What do you think that says about you?
If you don't have a favorite hand, what do you think about players that do?
To me the answer either way lends to personality and preferences.