What are some of the best science fiction movies of all time?

There have been a number of well received science fiction movies including classics such "2001: A Space Odyssey", "Star Wars", "Blade Runner", "Alien", "Inception", "The Martian" and "The Matrix". Often the most important factor of what makes a movie great is very dependent on the viewer themselves. Are they interested in movies that are based more on hard science like "The Martian" or more like a soft space opera or fantasy like "Star Wars". Movies can also be great commercial successes while not being critically acclaimed. Some movies can also be great action films or be very thought provoking or reflect on bigger themes like the nature of being.