I'm surprised this segment hasn't been put in here. Watching Dave "hulking out" on the Simon System before and during the match was pretty funny. His "salesman" pose at the end...I busted a gut laughing.
Pretty much all of his final run in WWE, in which he was easily the biggest douche walking the face of RAW in the last five years.
Any backstage segment he had with Eddie Guerrero, and of course the in-ring segment where Batista goes "Tommy Boy" on him and demands a hug, complete with Eddie's priceless face.