Well, being a woman myself, I really guess I'm giving my perspective of what guys say they have noticed on me, first. First of all, I keep my butt in good shape. Round and nice. Most guys notice that first, at least that's what my boyfriend loves the most!lol. And I have a teeny waist. (Which he also loves, because he's so tall and I'm so petite) Next, they say eyes, because I have hazel eyes that are more green than brown, so they're a little unique.
BUT, from my observations of my guy friends and my boyfriend's friends, I would say that about 75-80% of them look at the boobs first. I always tell them, "Okay, so she has big boobs, but her face isn't really that pretty!". And their response alot of times is ususally "Who cares!". I suppose they figure that the boobs are there to just look at, but when it comes to relationships, I think men look at different things: eyes, lips, etc.
<3, nikki