I agree with the notion that there is a difference between what you notice first and what is the most attractive feature, unless you're talking specifically physical features, which seems to be what the other men have assumed.
I find myself paying attention to the woman's figure when I first see her. Wide hips, big breasts, and a comparatively smaller waist. Of course it doesn't have to be that great for her to be attractive to me. The thought, "What if she's beautiful on the inside too?" is what motivates me.
Well sometime it depends on the girl. If I haven't talked to her yet and she is just walking by, I always look for a nice ass but some girls don't have a nice ass but have great boobs or face or a nice body in general so it depends. After talking to her if she is just plan stupid then it doesn't matter. That's a turn off.