I have a different theory on why nice guys lose and jerks get the girl.
One thing about nice guys is that they are usually "genuinely" nice, but not always. When I say "genuine", I mean truly self-less and charitable (if you're Christian, think Jesus-like). However, when they meet a girl that they like or find attractive, they will be extra nice, but with the intention/hope/wish of the girl liking him for his kindness. So it's no longer doing something nice for the sake of doing something good, but for the sake of possible hanky panky. "Nice" guys will go to extreme lengths to make this girl happy, and there's nothing wrong with doing that. But more often than not, it's not truly genuine. I base that on the fact that guys will complain about some girl not like him that way even though he did lots of things for her.
The reason why girls like jerks (it's not the absolute truth, but it's somewhat true) is NOT because they're jerks, but because jerks have characteristics that are attractive to women (i.e. confidence) which "nice" guys don't have around girls they're interested in. Jerks aren't afraid to tell a girl what he really thinks whereas a "nice" guy will sometimes hold back and not say the truth.
The jerks also tend to be more of a challenge in a relationship, whereas a "nice" guy will declare his love from the moment they meet and put her on a pedastal asap. That's where that other cliche comes into play, "the ones you want, you can't have, and the ones you can have, you don't want."
And in closing, I've noticed this Catch-22 about nice guys. "Nice guys" are usually great friends and great husbands, but they tend to be lousy boyfriends. And if you can't be a great boyfriend, it's almost impossible to become the great husband (assuming you're looking for marriage), and thus the "friend zone" is as far as you'll ever get with the girl of your dreams.
Kancho