For me, it has to be both. I'd be selling myself short if I went any other way.

Initially, looks will attract me. However, I immediately have an assumption that anyone who is attractive is an idiot. (Okay... initial assumption that everyone is an idiot.) At that point, I dismiss them as potential until it can be proven to me that they are intelligent enough to have a deep conversation, share my sense of humor, and share my values.

I definitely need to connect to him or her physically and mentally. Otherwise, sex would suck and conversation would suck. Plus, nothing is better than being able to hang out with someone you like to have sex with and having sex with someone you like to hang out with.