It's a pretty safe bet the most hated teams are usually the most successful:
MLB: Yankees, Red Sox, Dodgers, Giants (among some others)
NBA: Lakers, Celtics (hatred for these two probably eclipse all others, including the Miami LeBosh)
NHL: Red Wings
NFL: Everyone hates the Patriots
MLS: No one hates on teams they don't watch
Don't follow international sports too much, so I don't know of any "most hated" teams, although I'm sure Manchester United is up on that list somewhere.