You know, all this talk about science fiction movies and no one has mentioned Blade Runner. I'm really kind of surprised.
In a way, Blade Runner
defined the genre. Blade Runner was plot and mood (ESPECIALLY mood) intensive. And while being nearly nothing like the book it was based on, it sort of set the standard for what followed--a standard which most SF films simply couldn't match.
To put it another way, it was one of the first SF films where the the two main faces of written science fiction--hard and soft--were merged. Hard--the androids, the flying police cars, etc; and the Soft--the social differences of the future--the polyglot society, the sacredness and definition of life, and so on. Most of the SF movies until then were mostly spaceships and gadgets, or easy-to-spot aliens with no redeeming qualities.
The Twilight Zone is a good example of Soft SF--of how individuals and societies behave or react when "Hypothetical X" occurs.
Star Wars didn't really get metaphysical until Episode 1; and then just enough to further the plot.
