i figured i would post the results of the hand, just so people could see what he had and comment on the likelihood of his holdings.

River:

Hero: Bets $45
Villian: (Waits for about 20 seconds) calls $45
Villian: turns over K-K (which i guess justifies his flat calling IP preflop)

I win!
But, after reading your comments and not being in the heat of the moment, i think that this hand was kind of a fluke. most of the time he probably has a set, or a drawing hand and i should check to him on the river and let him either make me pay him when he has a monster or him pay me with a missed draw (assuming someone so aggressive would try to steal the pot after 2 checks to him when he has nothing).