Call me shallow, but I would never go out with a girl who was ugly but had ' a great personality '. Im siding with Zlatan on this one, he shouldnt settle for less when he can get someone better.
Personality could also make her seem more attractive than she really is. So i think it counts a great deal. Because eventually, that's what will keep things going. Butt ugly would need one helluva personality to layer it, although i think it could still count a great deal. At the end of the day however, an ok face, and decent personality would suffice. (Even if we can do much better.)