Visually, you cannot beat the Darth/Luke battle scene in the carbonite freezing chamber in ESB.. it is like art. The orange and the blue are so beautiful
Unironically, "you were my brother, Anakin. I loved you" though I suppose it is more of just a line rather than a whole scene. Ewan was too good for those films.
There are so many good ones but here are a couple that came to mind when I saw this question:
From RotJ: “Never. I’ll never turn to the dark side. You’ve failed, your highness. I am a Jedi, like my father before me.”
From ESB: "I don't believe it!" "That is why you fail." plus Yoda's "luminous beings" speech.
From Andor: Kino Loy's "one way out" monologue over the intercom during the prison break.
Han Solo in the cantina
Battle of Hoth
It's a trap! battle
Vader hallway in Rogue One.
The opening scene. Lots of movies had featured spaceships like the one we initially see fleeing. When it reveals the size of the star destroyer, we know that it's going to be a new type of story.
In The Phantom Menace, the entire podrace scene. Yes, it's goofy as heck, but man does George Lucas know how to make some pure campy exciting fun.
In A New Hope, the trench runs. God, they're just SO COOL, especially on a big screen.
In The Force Awakens, Han being rescued by the Resistance, from the time Han Solo is captured to the time Leia shows up, is a masterclass example of editing and music.
Darth Maul revealing his double edged lightsaber and the entire duel of the fates battle.
Lots of beautiful visuals in Rogue One, especially the final battle and Vader’s scene.
Anakin and Obi Wan’s final conversation as Anakin is dismembered and burning.
Criticism aside, the Holdo maneuver was visually amazing in the movie theater.
Luke and Vader’s final battle and Palpatine joining.
Luke looking up at the 2 moons + the score.
Unironically, the original trilogy credits always got me pumped up for the next one.
Since everyone is saying movies, I'm gonna say the scene before Order 66 in The Clone Wars
I’m really surprised no one has said the tragedy of Darth Plagueis scene from RotS, Ian McDiarmid is fantastic.
