I'm your perfect girl! Haha. :PI agree with behoopd -- trust is very important. I have to be able to trust you, and especially trust you not to judge me. If you can trust me, then that's where things really can be great.
Generally, what else I look for is this: brains, depth (emotional), potential for humor, and attractiveness. If they have an open mind as well, in addition to some of these other traits, chances are good that I will really like you then lol. Girls who are comfortable with themselves and aren't neurotic about being perfect really I find attractive. Big turn-offs for me are girls who are extremely loud and unconscientious of others' feelings, don't care about anything or anybody, and try to argue all the time, trying to prove how "smart" they are.