When someone is attractive, people say things like he has a cute face or she’s got a pretty face. Sometimes they single out just parts of the face and say things like he has a great smile or she’s got nice eyes. Rarely, however, do people compliment the whole head. If the person does have a nice head, I think a compliment addressing the whole head is in order. Something to the effect of “he or she has got a pretty good head” would be appropriate. The word cranium could be substituted depending on the person in question. Noggin, noodle, biscuit or block should probably never be used.