Sci-Fi is always loosely defined, but anyway here are my top 10 that have some kind of sci-fi theme:
1. 2001: Space Odyssey (1965-8)
2. Logan's Run (1976)
3. Invasion of the Body Snatchers (1956)
4. Star War IV: A New Hope (1977)
5. The Thing (1982)
6. 12 Monkeys (1995)
7 Total Recall (1991)
8. Planet of the Apes (1968)
9. Westworld (1973)
q0. Forbidden Planet (1956)
As you see I like the originals, not the remakes.
Honorable mentions: All 1960s Gamera/Godzilla films. The Time Machine (1960)
Alien
The Day the Earth Stood Still
Invasion of the Body Snatchers
The Thing
Forbidden Planet
Planet of the Apes
Village of the Damned
The Terminator
Bladerunner
Children of Men
1 repo man
2 2001
3 invasion of the body snatchers (1956)
4 stalker
5 videodrome
6 12 monkeys (gilliam's best, imo. to me, brazil is a failed, ambitious mess - this is where he go it right) + la jetee (cheating by including both here)
7 timecrimes
8 dark city
9 the day the earth stood still
10 world of tomorrow episodes 1+2
i made this list in response to a thread on another site about 1/2 a year ago when someone posted paste magazine's 100 greatest sci-fi list. i think it's a fun list - some things i love, some that i don't, and quite a few i need to catch up on.
I never even liked the Body Snatchers idea but I came up with a killer concept for a remake that makes it even creepier, and actual legit science fiction with new ideas.
Im gonna write it, and the term "invasion" is going to have a whole new meaning.
1 The Thing (1982)
2 The Terminator (1984)
3 Blade Runner (1982)
4 Alien (1979)
5 Star Wars (1977)
6 Metropolis (1927)
7 Invasion of the Body Snatchers (1978)
8 Aliens (1986)
9 Split Second (1992)
10 Yor, The Hunter From the Future (1983)
Contact
The Empire Strikes Back
Eternal Sunshine of the Spotless Mind
A Clockwork Orange
Blade Runner
Prometheus
Solyaris or Solaris, both really good.
Mad Max Fury Road
Gravity
Idiocracy
The Terminator (1984)
Forbidden Planet (1956)
The Day the Earth Stood Still (1951)
The Thing from Another World (1951)
Blade Runner (1982)
Total Recall (1990)
12 Monkeys (1995)
The Empire Strikes Back (1980)
Dark City (1998)
Close Encounters of the Third Kind (1977)