I’ve actually read something that fits my own personal experience: that attraction for women is more dynamic than for men. I’ve known quite a few women who tell me they weren’t initially attracted to their husband, to the point where they refused to go out with them at all. With the men, however, it seems far more often that they were enamored with them the first time they saw them. So what I’m saying is that once a man determines whether you are attractive or not, it seems he’s much less likely to change his mind.
Another thing I’ve read is that a guy tends to be attacted to you, and then falls in love, while women seem to fall in love and then find you attractive. Now this I’ve seen a lot more exceptions to, but mostly on the female side. I’m sure there are men who fell in love first, or who changed their mind about how attractive a woman was, but it seems somewhat rare*.
Oh, and for the record, I don’t believe I’ve ever fallen in love. I’ve merely been infatuated. And while I’ve had my affection grow for women I don’t really find attractive, it’s never crossed into us being any more than really, really close friends.
ETA: And what ultrafilter said. When I was thinking about type, I, like Lunchy appeared to, just consider women I’m attracted to. In other words, I only thought of three types: women I’m attracted to, women I’m not, and those rare ones that are hard to place.