I like a man I can sink my teeth into. For instance:
1. Joaquin Phoenix
2. Mark Ruffalo
3. Stephen Colbert
4. Lewis Black
None of them is leading-man handsome, but they all possess a certain (and attractive) intelligence. A sense of humor goes a long way, too.
In unrelated news: The recent torture killing of a young grad student in New York City has completely freaked me out. It underscores the sad fact that just because a woman thinks she knows somebody (in this case, the bouncer in the bar where she was hanging out) or the man seems to be in a position of some authority, it doesn't mean he's a good person.
If you're going to hang out in a bar, go with a friend and go home with a friend. No exceptions. If you meet a guy who has great potential, plan to meet him again in a neutral location. Remember what your parents told you when you were five: Don't get into a car with a stranger.
He probably wouldn't end up strangling you with your pantyhose, but why would you ever risk it?