I've dealt mostly with women of the latter type Venhardi describes--not girls who are just a little down on themselves, but who have undergone some pretty serious shit.
I was actually talking to someone about this last night. I am mainly attracted to two kinds of women:
1. Damaged, vulnerable, standoffish women who have trust issues.
2. Smart, funny, confident, and (sexually) freaky women who are very much not "damaged" but I find fascinating for different reasons altogether.
The odd thing is, a #1 can turn into #2 over time.
The important thing to remember is that you can't go in trying to save them. You can try to help them, but they're the ones who have to do the work of sorting themselves out. But Venhardi is right, it's not easy to have a relationship with them. And if they do "get better," they will be very different people in a lot of ways.
Still, I do it because I have kind of a surplus of affection to give and I just have a natural tendency toward helping people. If they decide they don't need me anymore, that's just how it goes sometimes.