How about this vintage one?
http://static.funnyjunk.com/pictures/tennis_20girl_20450.jpg I'm a huge tennis fan...

Also one of my favourites:
Cindy Crawford.
http://hotcelebrity.name/wp-content/uploads/2009/08/cindy-crawford-picture.jpg

Plus, I like some of the new Ashley Greene Bodypaint images too.

Too much choice, I'm afraid :-)

Why they are so great? Hmm. Tough one. On the first one, it is quite simple, the photographer captured a secret, and innocently erotic moment, which makes you feel like you get to see something you are not supposed to see.

For the bodypaint pictures, well, I think it is knowing the amount of work that has gone into applying the art, plus the knowledge of the fact that basically, you are looking at a woman in the nude.

I guess the Crawford picture is more or less the same deal: You get the idea of seeing just a bit more than normally would be 'proper', in a quite subtle way.
It appears to be a tight balance between revealing enough, and not revealing too much which make them sexy.

This one: http://barefoot.provocateuse.com/images/photos/marcus_schenkenberg_05.jpg
...is my favorite.

This was hard to pick--I could think of a lot of images that fit the bill! I like this specific image for a lot of reasons. First, Marcus is exactly what I imagined a character in a book I've been working on for years would look like. I hadn't seen him before writing the character, so when I first saw a picture of him, it was like meeting my character face to face. So I'm sure that has something to do with it.

He's shirtless, so there's the obvious sexuality of the pic. But he's also got the look of a somewhat tough (as in outdoorsy, not as in thuggish) and confident man, sort of like the whole Man With No Name mystique. I like that he's carrying his boots and walking barefoot. It makes me think of a story that goes with the picture, and I want to know more about him. WHY is he out in the desert like that? Did he lose a bet? Get robbed? His horse ran away?

I get fantasies of being the woman who rides by, looks him up & down, and offers him a ride back to civilization. :) With a stop at her (my?) cabin on the way, natch. ;)

You really want beautiful? I'll show you beautiful, and you can take your pick.

Whether it comes in the form of a photo or film, nothing beats the image of a classic beauty presented in black and white.

http://upload.wikimedia.org/wikipedia/commons/8/88/Marilyn_Monroe_in_Some_Like_it_Hot_trailer_cropped.jpg
http://en.wikipedia.org/wiki/Marilyn_Monroe

Sometimes the beauty comes from a fond memory you associate with the time period or the clothing and jewelry in the photo. Sometimes it comes in the form of a haunting look or a sweetly funny expression. Sometimes it has more to do with the way a personality shines through to the observer no matter how many years have passed.

Consider, for example, this Milton Greene photo of Marilyn Monroe:
http://www.greatmodernpictures.com/mmn03.jpg
http://www.greatmodernpictures.com/marilyn.htm

And this collection of Marilyn Monroe photos on video:
http://www.youtube.com/watch?v=im2wQLb05V8

Of course, there are many other gorgeous examples to enjoy:

http://www.youtube.com/watch?v=ruZmzVirF34

http://www.youtube.com/watch?v=-YImKfO_BQY

http://www.youtube.com/watch?v=_WjNj1R6dcc

http://upload.wikimedia.org/wikipedia/commons/4/43/Ginger_Rogers_Argentinean_Magazine_AD_2.jpg
http://en.wikipedia.org/wiki/Ginger_Rogers

http://upload.wikimedia.org/wikipedia/commons/6/6f/Mae_West_in_1953.jpg
http://en.wikipedia.org/wiki/Mae_West

http://upload.wikimedia.org/wikipedia/commons/d/de/Dorothy_Dandridge_in_The_Decks_Ran_Red_trailer.jpg
http://en.wikipedia.org/wiki/Dorothy_Dandridge

http://upload.wikimedia.org/wikipedia/commons/c/c9/Lucy_YankArmy_cropped.jpg
http://en.wikipedia.org/wiki/Lucille_Ball

http://www.youtube.com/watch?v=CZrEcI-ULbQ

http://www.youtube.com/watch?v=ilykaP9B7tk

Need I say more? I think not. :)

Robert Pattinson and Kristen Stewart's real life love is apparent in many candid photos taken of them. They deny that they are in love in real life, but I feel these photos speak for themselves. So beautiful! See my link below for a whole Mahalo page that I made about Robsten's love.

This picture is of a Navy Wife waiting for her Petty Officer husband as his ship docked from a deployment in the Persian Gulf. They had only been married for six months before he was deployed. The picture first appeared in the Virginian Pilot but was plastered all over the USA. There is something about this photo that has stuck in my mind.