The final scene of Robocop (the original 1987 version).
“Nice shooting, son. What’s your name?”
“Murphy.”
Very often the understated – or simply unstated – looks precisely like an error. Which we are pledged to correct.
The Long Good Friday: Bob Hoskin’s mob boss realizes his fate. No dialogue; the expressions on his face tell all.
+1.
I also liked the telephone scene – the one where the dead man’s wife conveys the news of his death to the other guy. (Sorry, I can’t get the names straight.)
While watching this visceral and sad scene, I was thinking that it would be hard to top it in terms of the emotional punch, but the last scene did it. I didn’t see that one coming.
The Seven-Ups, where Roy Scheider tells his double-crossing informer that the mob has “learned” of his treason, and the audio goes completely silent as he gets in the car and drives away, leaving the informer framed in the rear window, screaming and raging after him.
Which pairs nicely with the opening of Falling Down, totally silent until…
Spoorloos (The Vanishing), very dark (both figuratively and literally).
Thelma and Louise.
And then came the TV movie rip-off: “Mr. Louise,”
Then the “official” sequel: “Wanted: The Louise Man,”
Then the “prequel” : “Thelma and Louise: The Early Days.”
I like you anyway, burpo. 
It’s REALLY hot outside today. Did I type all that? 
GalaxyQuest.
Tons of great closers already mentioned!
I just saw Jaws on the big screen tonight in Hollywood. Never got to do that before, I was 4 1/2 when it came out in 1975. So great to watch without commercials too.
I love this ending because it shows a long shot of Hooper & Brody kick swimming their makeshift barrel boat while the credits start. The screen doesn’t go black until they’re both on shore and safe. Not killed by shark or hungry seagulls, but not at home. They’re stil stranded for a few days I suppose.
“I used to hate the water. I wonder why.” 
The best part is that at the end, the very end, he allows himself to smile just a bit.
I saw an interview once that the whole taxi scene was shot in live NY traffic, and that people in nearby cars and on the sidewalk were constantly catcalling him and trying to catch his attention. So the whole time you see him “thinking”, he’s actually trying to keep a straight face while a bunch of New Yorkers are shouting “Clooney!, Yo, Clooney! Whatcha doin’, Clooney?”
-The Unbearable Lightness of Being: the main characters are in a car, almost to the peak of a hill, and there’s a truck coming at them on the other side – we know they will be killed, but the film ends a nanosecond before it happens.
I drive a hill on the way to work and think of this scene every doggone times.
-American Beauty
-Antonia’s Line
“The Cuckoo’s Nest” must surely be mentioned in a thread like this?
The Ending to which All Other Endings aspire!
I liked Snake Plissken’s final scene in Escape From New York.
The whole story revolved around Snake’s assignment to rescue the President and a cassette with the President’s recorded speech to be delivered before a Very Important International Conference. In the movie, another cassette appeared containing rock (or maybe it was rap) music. Snake rescues the President and delivers the cassette, which is played at the conference – and it’s the music tape instead of the speech. Final scene shows Snake walking away with the real cassette, pulling the tape out of it.
It was Cabbie’s tape of “Bandstand Boogie”.
I love the ending of Withnail and I. Withnail and Marwood parting for what is assuredly the last time … his tearful Hamlet recitation to the wolves … then walking off into the rain with his bottle as that maudlin, carnival-sounding song that might as well be called “Withnail’s Theme”* begins to play.
*(checks Wikipedia Well I’ll be damned.)
A generally underrated movie The Upside of Anger has a great ending. I remember thinking it was a pretty good movie overall but the closing scene made it unusually memorable for me.
Better or worse than the prison concert in The Blues Brothers?