Solaris
I recently watched Steven Soderberg's remake of the 1972 Russian film "Solyaris" which itself is an adaptation of Stanislaw Lem's novel of the same name. (And, as usual, as soon as I find out about an interesting author, I also find out he or she has recently passed away. In this case, Lem died March 27th, 2006)
Andre Tarkovsky's original film is said to be a stunning masterpiece of a movie. I've not yet seen it, but it must be something because Soderberg's version is really quite amazing. Essentially there are 5 people in the entire film. Very little is said, but there is a lot of emotion. Many questions are asked and left unanswered and time flows in mysterious ways. Voiceovers do not always match the scenes being show which, for this film, is a really good effect. It's a very slow paced film, but so full of tension that there's really no other way this would have worked.
And to top it all off, Cliff Martinez' score for the film is powerful. It's almost another character in the film.
The movie I watched right after this was the low-rated "Red Planet" (Carrie-Anne Moss, Val Kilmer). Certainly not high-art, simply a bit of entertainment fodder. But I was rather surprised at how "Solaris" threw its short-comings into such sharp relief. "Solaris" forced me to focus on the film, on the characters, and on the story. But watching "Red Planet" I could drift in and out without really caring. (Indeed, I finished watching the movie while assembling the crib.)
Anyway, go rent "Solaris."