The most important thing to me in a woman is that she be someone I can argue with. I do not mean someone I will fight with — I have no tolerance for fighting –, but someone that I can debate with rationally and yet also intensely passionately. Four things are required for this: she must be intelligent enough to be able to not only keep up with my points, but find fault with them; she must be passionate enough to not relent when I keep pushing harder and harder; she must have enough self-respect to not concede to me because she thinks that I know better; and she must be someone whose behavior merits my respect such that the noble words coming out of her mouth do not sound hollow and self-indulgent to me. Give me these four things in any woman that I do not find ugly and I will fall in love. Take away even one from a person I love and my love dies.
Astoundingly, I think there may be nothing more to be said on the topic than this one paragraph.