I think it differs from person to person. Personally, I’m much more likely to indulge in a random hook-up than I am to actually date a girl. This is for a lot of reasons.
In order to hook up with someone I really just need to be attracted to them at that moment, and it really only needs to be physical attraction. Maybe she’s looking really good that night. Maybe I’m drunk. Whatever.
There have been times when a girl’s personality has been a total deal breaker, but it’s a lot more difficult to screw up a hook-up than a potential relationship because it’s easier for me to overlook a bad personality, or one that just doesn’t mesh all that well with mine, if I don’t intend to spend more time with them.
Beyond that, I don’t generally actively look for relationships. The only times I pursue it are if I’ve met a girl and we just seem to click in multiple ways. I’m not against commitment, but I’m not seeking it, either. I’m willing to take that plunge if there’s a sufficient amount of chemistry between us, but I am not the type of person who will date for the sake of dating. If I decide to ask a girl out on a proper date in the first place I’ve probably already decided that I can easily see myself with her for a while.
In order for me to really date someone I need to be able to talk to her easily, we need to share a few similar interests, she needs to possess (or at least appear to have) certain values/virtues, she needs to be reasonably intelligent, and she has to be at least somewhat attractive (at least to me).