Knife in the Water (1962, Roman Polanski)
I like how the woman who stays in the shadow throughout most of the film calmly maintains control of the situation, plays the two men like the children that they are, and comes out the winner in the end.
Loved the tight plot, the tensions bubbling underneath the more or less civil facade, the subtle dynamic between the three characters, and on top of it all, the absolutely beautiful, crisp black-and-white cinematography by Jerzy Lipman (who also worked with Andrzej Wajda). A classic, deservedly so.