I'm still with my first love, too, but I have a few crushes to go off of.
I'd have to say that an aura of confidence is big for me. Obviously, it's nice thinking that he's not going to crumble at the first sign of adversity -- but also, it's hard to be yourself in a relationship with someone who's not confident, because you spend so much time trying to protect them or bolster them. They're a lot of work.
Humor is great, too... especially if it's the same cheesy sense of humor I have. It's light, fun, easy, and -- if you both have the same, odd sense of humor -- it's something you two can share. Also, if someone understands your humor, they really understand a lot about you and your outlook on life, too.
Can't forget brains, either. I have no interest in hanging around guys who aren't up to, or above, my level. It's fine if they're proficient in a completely different subject than me. For example, I'm an English major working as a web editor and my boyfriend is a business major looking for HR management jobs. But we can still carry on a great discussion, and in fact, I'm constantly learning cool stuff from him because of our different perspectives, and he challenges me to keep thinking in different ways.
And I have to admit that just about every guy I've had a crush on has curly hair.
Why? Probably because as a kid, every time my mom saw a curly-haired little boy, she'd coo about how handsome he was going to be. lolprogramming.