Well, obviously, hot chicks are a turn on, but that gets freaking destroyed if the chick is dumb. I can't stand people that refuse to educate themselves. And to the contrary, smart chicks damn near make me pop insta-boners. That, and if after sex, I ever hear the phrase; "So do you want something to drink, and maybe a sandwich?" I getting married right then and there.
Oh and to the guy that wants a chick to think sex is not important......WHAT! Dude, you're asking to get stuck behind every episode of Sex and the City while pitching this HUGE tent, and falling back on your word constantly.