Well, what about this version?
The 1978 version of Invasion of the Body Snatchers, starring Donald Sutherland and directed by Philip Kaufman.
The plot is, essentially, the same one as the original movie: Matthew Bennell (Sutherland, called "Miles Bennell" in the original) is a local health inspector (doctor in the original) who starts hearing reports of people saying that their loved ones aren't themselves - that they've been replaced. His friend, Dr. Kibner (played wonderfully by Leonard Nimoy) dismisses this as simply "hysteria," but the truth is that they have been replaced by people grown out of alien "pods."
The beauty of this film is that is essentially replaces the original films metaphor about post-war panic with Cold War paranoia. In the original film, Bennell is essentially telling his story to the audience about this new danger - the danger is real and we could be next if we don't act fast. In the studio-mandated ending, the authorities do act fast and stop all the pods from spreading - an executive-mandated happy ending.
Nothing like that happens in the 1978 version. No, it's much more bleak here. The danger is real and the danger is here...but nobody can stop it. You have to sleep sometime. And who can you trust? Your friend? Your lover? They have been replaced. Even the ending to the movie (SPOILERS) has one of the only surviving characters ending Bennell and whisper to him...only for him to point at her and let out a pod-person scream, revealing that he is, of course, one of Them. They are everywhere and you cannot escape Them.
People who loved the original version should definitely see this one. In fact, people who love horror films laced with paranoia fuel should see it. It has wonderful displays of acting by Sutherland, Jeff Goldbum, Veronica Cartwright, and, of course, Leonard Nimoy.