When I check out other women, I usually notice the neck, the hips, the curve of the rear, also her lips and when naked I like the dimples that some women have in the small of their back.
Naturally I then notice their eyes, breasts, hair and feet.
I like a woman who has some curves - breasts, hips, butt. At least in moderation, not too big and not too small. And here is one that has not been mentioned yet - skin. I get really turned on by nice, soft skin. I think when we start talking about parts, we need to remember that what really counts is the WHOLE package- and that includes personality! A woman can be " hot" but bitchy, and that is a real turn off for me. I like women who have a warm, soft, inviting look about them with a personality to match!