Everyone loves alien movies, and as with my vampires movies thread, this one will be to discuss our favorite. You can discuss the movies, or your favorite aliens and why. As far as aliens go, I've always felt that nothing compares to the AVP franchise,taking the good and bad as a whole. Star Wars may be the pinnacle of sci fi, in the sense that it is broad spectrum and far reaching, but the Aliens movies made the idea of encountering lifeforms from other worlds, truly frightening.
The Far Out
Star Wars (all of them included here, just too many to list)
Predator
Predator 2
Independence Day
Alien
Aliens
Alien Resurrection
Avatar
ET
Prometheus
The Good
Dark City
Species
Species II
The Astronaut's Wife
Alien 3
Pitch Black
Close Encounters of The Third Kind
The Thing
Alien VS Predator
Alien VS Predator 2
District 9
Slither
Contact
Cloverfield
The Faculty
War of The Worlds
The Ugly
Invaders From Mars
Apollo 18
Signs