I have over 500movies on my external hard drive and a lot of them are sci-fi, so if you only know the mainstream list of sci-fi movies, I am not interested. But if you got some that are sci-fi that not everyone has heard about then that be great.
Pandorum
Natural City
The Host (not sure if that's quite scifi, though)
Endhiran (also spelled Enthiran)
the "Krrish" series
Screamers (http://en.wikipedia.org/wiki/Screamers_(1995_film))
Paycheck
A Scanner Darkly
I don't know what movies you have and haven't seen. Here is a list of my favorite SF movies.
2001: A Space Odyssey (1968)
The Abyss (1989)
Alien (1979)
Aliens (1986)
Alien Nation (1988)
The Andromeda Strain (1971)
Blade Runner (1982)
Close Encounters of the Third Kind (1977)
Dark Star (1974)
ET: The Extra-Terrestrial (1982)
The Fly (1986)
Galaxy Quest (1999)
Marooned (1969)
The Matrix (1999)
Men in Black (1997)
Metropolis (1927)
Minority Report (2002)
Pitch Black (2000)
Planet of the Apes (1968)
Predator (1987)
Robocop (1987)
Rollerball (1975)
Silent Running (1972)
Star Trek II: The Wrath of Khan (1982)
Star Wars Episode IV: A New Hope (1977)
Stargate (1994)
Starman (1984)
The Terminator (1984)
Terminator: Salvation (2009)
The Thing (1982)
THX-1138 (1971)
Tron (1982)
Twelve Monkeys (1995)
Westworld (1973)
.