2001: A Space Odyssey

When you look around at lists of the best science fiction films, it is nearly impossible to find one that does not list 2001: A Space Odyssey at the top. You have to dip into the moron-space to find such a list. The people who think Star Wars is science fiction tend not to like this film, but even they will put it on their list. It has become the Citizen Kane of the genre, so everyone puts it at the top of the list.