I typically don't rate anyone. However, if I did, it would mostly be for the face. If the girl doesn't have a pretty face, I couldn't possibly care less about what her body looks like. As long as the girl isn't completely skeletal or overweight, the body matters very little to me.
Face first then body each one out of five. Face first because it is more important. Put the numbers together so when you pass girls and they hear 33 or 43 or whatever they have no idea what you are talking about. Well at least its a little less obvious then saying 6 or 7.
Being a guy, I like a girl to have a good face and a good body; but the face comes before body for me. But one great factor for me, which I guess most other guys don't even consider is a girls personality...:)