There's a great post by Ide Cyan over on Feminist SF: The Blog! on two recent vampire movies - Låt den rätte komma in (Let the Right One In) and Twilight. Though I haven't read Twilight or seen the movie, I was very interested in her analysis of its popular appeal:
Twilight’s popularity is intimately tied into the gendering of romance. Love stories do impress women with the importance of finding a lover of the opposite sex, to fortify the institutions that are at the basis of a patriarchal society. Because we live in a patriarchal society, it is with individuals from the class of their oppressors that women are encouraged to find romance. The mystification of oppression consequently blurs the distinction between the ideal lover and the lover as he represents a source of oppression for a woman.
There's good discussion in the comments, including the opinion of a feminist SF fan from Sweden on genre movies there.