They're both important really. It's damn frustratiting to always see personality and beauty talked about as two separate, opposite things, as if they can never go together, or have someone have both qualities.
Being beautiful doesn't mean you have a bad personality, nor does being unattractive mean you somehow are a great person to be around with. Everyone has their own way of perceiving beauty. I'd like to think most men are attracted to blondes, but as for me, I am more attracted to brunettes. The prettiest women on earth can be a bitch, or a great person to be with. The same way someone horribly ugly can have a great personality, or a terrible one.
So, I'm not picking personality, or looks. I'm picking both. Although, I will always go out with a girl that has a better personality than one that is cuter.