Depends what the girl has. I can say i would notice her ass but its not applicable to women having well pronounced breasts cause i would obviuosly notice and aknowledge those.
So the first interest in a girl is her best asset. It could also be the voice. I remember hitting on a girl who had a really sexy voice and that made the rest of her look good. She wasnt noticable, but her voice made her so. Get what I mean ?