[kool bubba ice]

Matrix
Predator
Terminator 1
Terminator II
Aliens

 

[basementdweller]

SpaceBalls
Star Wars(old trilogy)
Star Trek (2009)
Gataca
Matrix
 
Honorable mentions are actually television series, but I can't not mention them as I enjoyed them more than the actual movies listed above:
 
Stargate(original and Atlantis)
Firefly
BSG(new)

 

[NorthWolfeCND]

1 - Blade Runner
2 - Alien
3 - Serenity (would love to get my hands on the idiot that canceled Firefly)
4 - Solaris
5 - The Thing(198?)
 
* Honorable Mentions for The Fly(80's)/Brazil/Predator/Clockwork Orange/Aliens/Matrix/Planet of the Apes(196?)/Donnie Darko/V for Vendetta/Mad Max 2/Stalker (1979)/Escape from NY
 
While I'm at it - the worst:
- Close Encounters
- 2001 (never managed to see it in one go - most boring flick I can remember, besides being ridiculous)
- Back to the Future
- Star Wars Ep. 1
- Cocoon
- E.T.
 
That's the ones I could remember. Unfortunately can't Google because browser crashes with more then one tab open...

 

[Redcarmoose]

The Day the Earth Stood Still (1951)

 

Solaris (1972)

Planet of the Apes (1968)

Mad Max (1979)

Space-Thing (1968)

 

[shigzeo]

Back to the Future
2001
Naked Space 

 

[Sadkmf]

Blade Runner
2001
Matrix
Alien
Island of Lost Souls
 
Hate: Sunshine, Inception, Stalker..