At the point where you begin to deconstruct the movie that much, I think you need to read the book. It would be a completely different version of the story of course, and the answer you received would likely not be one you desired, but it would be an answer nonetheless. I would try to lay it out for you, but I cannot do it as well as this person did. Warning: some spoilers on the book's plot in there, nothing you haven't already seen in the movie though.
I don't think I've seen these mentioned, three of my favorites. 12 Monkeys Starman Close Encounters of the Third Kind
the day the earth stood still. i think that might be the most influential or most alluded to, in other sci-fi flicks, of all time.
Time Bandits - "Mom! Dad! It's evil! Don't touch it! Mom? Dad?" Scanners - Huge fan of Cronenberg and exploding heads. Soylent Green Food for thought. Donnie Darko My Catcher in the Rye of Sci-Fi. AkiraOne of my all time Sci-Fi and Anime.
