Philly fans can be pretty rough at times to me. OSU fans are right on par.
More and more though, I'm starting to really loath BC fans. They have horrendous inferiority complexes, never shut up or leave Irish fans alone, and I've met a few on message boards that have started gleefully talking about Charlie Weis (God forbid) having a heart attack b/c of his weight.
I have yet to meet the Eagles fan who tells me he hopes Tom Coughlin gets run over by a bus, or the Phillies fan who tells me they hope David Wright breaks his neck, so I think BC fans might have to take the cake for me.
As for the fans who are just bad b/c they don't support their team well enough, LA fans in general to me. They claim to be a baseball town, yet when I see Dodger games the stands aren't full by the 2nd inning, and they're empty by the 8th (even when the Dodgers are winning). Two football teams couldn't make it in the 2nd biggest market in the country (this is a sport that's managed to be successful in markets like Green Bay and Tennessee, but they couldn't make it there...). Had The Great One w/ the Kings for all those years, and they never really generated a ton of interest. Other than the Lakers, its tough to be a professional sports franchise in LA w/ those fans.