I'd pick two girls that decided to bully me one day. It was a pretty hard time for me and I never saw them again after I left school. I never had the balls to confront them at the time but I'd love to do it now.
my primary school teacher. he actually used to bully me (e.g. i was a pretty chubby kid and he actually used to make fat jokes!) and he once told my mother when SHE tried to confront him "i look forward to the day he's in the gutter". couldn't do anything though, it was a small irish village and he was in with the priest. sounds ridiculous but a few years ago that made you untouchable!