Spider-Man 3 gets my vote, although I like X-Men 3 as well. I boil up in side every time I have to listen to one of my roommates or classmates ragging on it endlessly, and then try to make fun of me for liking it. They can't even name a specific reason why it sucks, they just rant on and on about vague things like "the plot is full of holes!" and "there's no character development!" and dumb crap like that. When I ask them to NAME a plot hole, they always change the subject, and if I point out how a character DID get developed, then they just whine that it wasn't enough and that it was untrue to the comic. There is no way to please them, because they WANT TO HATE IT.
It's the same thing with Spider-Man 3, except they also whine about Sam Raimi's style, which was one of the reasons why I LOVE the Spider-Man movies. Some people just like to whine because it makes them look like more legitimate fans, I guess. My room mates don't really have a right to complain about SM3 and XM3 though, considering they thought Punisher Warzone was awesome.