Firstly, the usual things: love, loyalty, compassion, passion, trust, reliability, conviction; basically, an individual who is decent, has a good head on his shoulders, and doesn't do anything shady.
Secondly, compatibility. Once I find out a guy is decent, I'd like to know how compatible we can be. And this is different for every girl. I personally look for intelligence. I love guys who read or who are film enthusiasts because I spend most of my time talking and writing about books and films.
Most importantly, I personally seek guys who are family-oriented and traditional. Even if he possesses all of the above qualities but he is very focused on fame or money, I don't think it'll work because that clashes greatly with my goals in life. I'd like to start a family, spend time at home with the kids, provide for them, etc. I can't be with a guy who clubs every night or who needs to seek adventure because he can't enjoy the simple things in life.
It's really different for every girl once you go beyond the basics. You can still be a great guy but not "boyfriend material" for a certain girl because the chemistry isn't there or because you're too fundamentally different. I suppose this is where dating comes into play.