The original theatrical ending of Return of the Jedi. This troper never fails to tear up when Leia runs up and hugs Luke. For some reason this moment was shortened in the 1997 release onwards. and also, Luke seeing his father as the man he would have been had he not turned to the dark side, sharing a friendly look with Obi-Wan and then favoring his offspring with a loving smile.
The ending also has the entire galaxy celebrating when the second Death Star is destroyed, which means that the Imperial army is gone and freedom and democracy have returned. It's just... the fireworks, the cheering, the energy... *sniff*
The hug between Leia, Luke, and Han at the end of A New Hope after the destruction of the Death Star is another great moment. Their exhilaration is just beautiful.
Also, Han coming back at the last minute to cover Luke so Luke can destroy the Death Star is a great Big Damn Heroes moment. "Great shot, kid, that was one in a million!"
Plus, after spending the whole movie belittling him, C-3PO warns R2 to be careful as he heads out to attack the Death Star. "You wouldn't want my life to get boring, would you?"
And after the battle, upon seeing him badly damaged.
Threepio: (to Rebel technician) You must repair him! (to Luke) Sir, if any of my circuits or gears will help, I'll gladly donate them!
When Han and Leia visit Luke in the sickbay after being attacked by the wampa.
Han: Don't forget, that's two you owe me, junior.
And it's brought up again in ROTJ:
Han: Hey, Luke, thanks. Thanks for coming after me. Now I owe you one.
Chewie's reaction to finding Han in the same cell in Jabba's palace.
When the heroes are about to be executed by Jabba:
It's blink-and-you-miss-it, but in the first movie, Vader says, "Only your hatred can destroy me." Think about it - there's a double meaning: it would kinda suck if your own son hated you, wouldn't it?
Also involving Obi-Wan and Anakin, Obi-Wan's interior monologue in the novelization of Revenge of the Sith where, after mutilating Anakin he realizes that he can honor the memory of the man his friend used to be by protecting Anakin's kids.
“Anakin survived it,” Obi-Wan said. “Luke can, too. And I can — well, I could take him there, and watch over him. Protect him from the worst of the planet’s dangers, until he can learn to protect himself.”
“Like a father you wish to be, young Obi-Wan?”
“More an . . . eccentric old uncle, I think. It is a part I can play very well. To keep watch over Anakin’s son—“ Obi-Wan sighed, finally allowing his face to register a suggestion of his old, gentle smile. “I can’t imagine a better way to spend the rest of my life.”