Given that this listing is a personal preference thing, there is a criteria I'd like all responders to follow. 1) Originality (no remakes, no book adaptations, no 'based on a true story'); 2) Intensity of Effect (includes "suspension of disbelief"); 3) Cohesion (logical progression though not necessarily linear); and 4) Complexity (no cliches, etc).
Do The Right Thing
The Empire Strikes Back
Dog Day Afternoon
The Deer Hunter
2001: A Space Odyssey
Brother From Another Planet
In the book of life, the answers aren't in the back. - Charlie Brown
"It is a profound and necessary truth that the deep things in science are not found because they are useful; they are found because it was possible to find them." - J. Robert Oppenheimer; Scientific Director; The Manhattan Project
"talking bull**** is not a victimless crime" - Marina Hyde, author.
Adapted literary sources are somewhat problematic regarding this particular list. You know? Would Apocalypse Now not qualify because it's "adapted" from Heart of Darkness? Or Blade Runner because it's based (loosely) on that Philip Dick short story?