Iaaa!! This is one of those "impossible" threads. You can shuffle the deck all night.
Here goes:
1. Carpenter's remake of "The Thing"
2. 2010: the Year We Make Contact (I'd love to have the "landlord" around when the IRS comes calling).
3. The Good, the Bad, and the Ugly
4. Apocalyspe Now
5. The Onion Fields (real-life version of Col. Kurtz in number 4: how far is the human mind willing to go to find a "solution"? As we've seen, a very few monsters, including Pol Pot and the Khymer Rouge will go quite far).
Ask me tomorrow and the list might change :confused: