There's a proverb in Japan: "You tire of a beautiful woman in three days."
I mean, obviously, everyone wants both. But a beautiful girl with no personality (or worse, a bad personality)? Please. You'd be better off taking a girly magazine to bed - all the looks, none of the headache.
But on the other hand, some of the way we look is actually directly connected to personality. A bright and cheerful person has a bright and cheerful face. Someone who actively takes care of themselves will have a decent body.
So I think if you really concentrate on personality, you can't go too far astray.