A certain question was asked of me recently which i shall here attempt to answer to the best of my ability using three lovely examples, to illustrate the point that although a man may simply appear to ogle females en masse there are different shades of eyeing-up.
Is it always lust when a man notices an attractive female?
The answer of course being a resounding No!
Not always...
1) Anna Friel: Without doubt, a very beautiful woman and like anybody easy on the eye, i would certainly notice her. Gazing upon a pretty face is a wonderful way to spend a moment but there would be no lust involved because she is just not my type. In Anna's case, i may appear to be ogling but i am only admiring.

2) Myleene Klass: Not only a beautiful face but also a gorgeous figure too, she could not fail to be noticed if i was nearby but whereas i quite fancy her, that clean-cut image just falls short of making me froth with lust. In Myleene's case, i may again appear to be ogling but i am merely wondering what she'd be like if she was a bad girl.

3) Fern Britton: Guilty as charged with Fern, she appeals to me on every level and fills my thoughts with the steamiest lust possible, thoughts which it's probably best hinted at but not detailed explicitly. I'd not only be ogling her like crazy but would also notice the living daylights out of her.

AnnaDawn
This was an eye opening post, I understand what you mean by "admiring" some people are just so pretty. I was at a water park and every one was running around in there bathingsuits, of course I was looking at the guys but I was also noticing the girls and thinking to myself "You know not one body is alike. Every girl is different." and thats where we're lucky.