Ehhhh, I dunno. When I was, well, 11, I thought Misty from Pokemon was attractive in a cute way, but now I see her as kind of a tolerable personality. Personality mixed with looks has been a winner with me since then, but keep in mind I like real women too, they just don't like me is all.
If you've ever seen Genshiken this whole "crushes on anime/game characters" notion is explained with a straight face and mature manner. Most guys who are into that sort of thing do actually like real girls as well, they just don't consider that they have a very good chance with real women.
Kinda like when I was 15 and had a crush on the character Yomiko Readman from Read or Die. It wasn't that she was 2D that she was attractive, it was that her personality and book smarts made her doubly so. And she wears glasses.
Anyway, video game characters can be sexy without even trying, depending on how subtle the game designer is. I mean if you're into athletic women even Faith from Mirror's Edge is sexy because she's so different to every other female game character you've ever seen. Yellow fever aside, if I needed a girlfriend who would go jogging with me I would date somebody LIKE Faith, not exactly Faith herself because SHE'S NOT REAL.