It's my philosophy that you don't hate people; you hate their actions. I hate all four actions in this poll, but I do not hate the people. I voted for the action that I think has the worst affects, not really the "people I hate the most."
By Klu Klux Klan, I'll assume you mean white supremacists in general. They aren't really all that bad, at least not as bad as they were in the 50s-60s. They base their dogma on fact, such as there are more blacks on welfare than whites, but then going anywhere from there (such as saying "blacks are parasites living off of this great country," or something like that--just about any racial generalization) is plain ignorant. But they generally don't go around bombing places and beating black kids and stuff (AFAIK).
As for Neo-Nazis, they're probably even more ignorant than the KKK, but they're certainly not as bad as the original Nazis.
And then on to homophobes. It depends on whether they simply think gays are bad and leave it at that, or if they beat up, kill, disrespect, etc. gays. Either way it's bad, but when considering they usually base it on religious beliefs that they've been taught by their parents to believe, it's not really "evil" to dislike homosexuality, as long as they give everyone, including gays, respect.
And lastly, fundamentalist terrorists. Even though everything on this list is wrong, I'd have to say terrorism is the worst. It kills people. It breaks families apart and frightens little children. The other three don't really do that (anymore), or at least not as much. This is the one I voted for. But in theory, all four can be equally bad.