I have three and in no particular order of loathsomeness:
Tom Cruise...because he's become a complete nut, and I wouldn't want people to think I was a nut too.
Paris Hilton...sure I'd get publicity, but the wrong kind. I'd be afraid someone would come up to b*tch-slap her, and they'd get me instead.
Jessica Simpson...because I'd never want to be around her very weird father and her even weirder hairdresser.
Add K-Fed , Aaron Carter, any Jack-Ass or any of the Hogans & you have my list.