To Starrsy: Paris Hilton was apparently in a game called "Paris Hilton's Diamond Quest," playable on cell phones. How she is actually incorporated in the game, I'm not sure. Count me in as one of those who wonder why the hell she got famous in the first place.
As for a character I want to beat the crap out of, there's only one, but I really hate him: Dalton from Chrono Trigger. I despise that idiot and hope that, if there is (gasp!) another actual Chrono sequel made, he's a boss that I can actually kill, not just defeat. I will take a sick pleasure from doing so. Stupid git.