What is your favorite sex scene in a movie?

I can't think of a particular one, but I came across a great project by IFC-

The best one I ever saw was in an Israeli movie called "Late Wedding". Here's a good description of the scene from Kinocite:

Their love scene early in the film is remarkable in its naturalness, forgoing gratuitousness to instead establish the intimate physical and emotional bond shared by the couple. And in a vast departure from Hollywood sex scenes, this one serves to make the eventual heartbreak that befalls Zaza and Judith seem all the more real.

There are also good sex scenes in many French movies, but I can't really remember which ones.

My favorite one is not so elegant but I guess the one in Borat .

the spanking scene in secretary :-)

It's not really a sex scene, but I find the scene near the end of ALIEN where Sigourney Weaver strips to get into her spacesuit and incredibly sexy scene.

Beyond Borders with Angeline Jolie and Australia with Nicole Kidman