Alien
I can literally watch it over and over. It feels perfect, and a lot of the crews' behavior can be justified with a little bit of creative thought. Maybe Ripley should've left the cat, but I like that scene, because if you'd never seen it before, it's supposed to make you think that Ripley might've just pulled a Brett (looking for the cat = death). Meanwhile, Parker and Lambert are together and armed (and Parker is the toughest of the crew) so it seems more likely that they would be less likely to be the ones that the crew would attack (from a certain point of view). Granted, you could also say that they were making more noise and were a bigger target than Ripley. I like the scene in retrospect because it really could go either way and until Jones jumps out and the scary music starts to play, you're not really sure who's going to buy the farm.
The movie's biggest head-scratcher as far as I'm concerned is the company and its behavior. But given that we have no direct contact with them, we're left to draw our own conclusions. Ultimately I guess it doesn't matter too much, but I wonder why they'd have to resort to such a gamble. All part of the movie's charm, and the company as far as I'm concerned is all the more mysterious and evil because we're so disconnected from them.
Why else do I love Alien the most? 1) Biggest, best sets. Great costumes and art design. 2) Small cast. 3) Dark, unromantic view of the future melded with a Gothic, mysterious view of an unexplored universe. 4) The best music (the original score as well as Jerry's Freud and the classical pieces used) heard in the series. 5) Also, the alien itself is my favorite in this one, in terms of how he looks and his behavior as a creature. 6) Ash is the best android (to be fair, the only Android I don't like is Call in Resurrection); there's a payoff with his character's behavior, with him breaking down in glorious fashion, whereas the other droids never really do. 7) Lens flare that doesn't make me want to pull an Oedipus.
Low budget, but it looks like a million bucks: Real sets, Animal gore. Miniatures and models.
The Derelict here and the way it is lit on the inside is perfect. Those glittering bones! 9) The Who's blue laser. 9) No guns. 10) Psychological depth, hidden themes, and complexity under the ostensibly "simple" action. Or, this film is pure art and can be interpreted a lot of different ways depending how you look at it.
I love Alien. : )