Lakers are the obvious choice, but they've won, so they (like us) can back up their/our talk somewhat. I always thought that last year and the year before that (But most of all, last year) the Cleveland Cavaliers were by far the most arrogant fans - I just knew that they would eat crow in the playoffs.
At this point in time, I think that Miami definitely takes the cake. They are so annoying, in that they think they already won. I have a really good feeling that they'll probably do pretty well in the regular season (fans will probably Edited. Profanity and masked profanity are against forum rules and may result in discipline. about a couple power rankings in the middle of the season), but get upset early in the playoffs (and I'm not even necessarily saying by us or Orlando).