For me, it's a tough call between anime-tards and the Twilight cult. The Twilight fangirls take an okay book/movie to the extreme, and it gets SERIOUSLY annoying. And then there's the anime group, as Tsun said, obese, Naruto-headband, ramen-eating, and shower-needing.
Not to say that ALL people who like Twilight are that way, or all fans of anime are that way. Not at all. I know plenty of Twilight/anime fans that can fangirl/boy in moderation.
My vote goes with Twilight though, as I can actually sympathize with the anime fangirls/boys, being a fan of anime myself. Whereas I never really liked Twilight.