In no particular order:
Babylon 5, Between the Light and the Darkness: When Ivanova went
"Who am I? I'm Susan Ivanova. Commander. Daughter of Andre and Sophie Ivanov. I am the right hand of vengeance and the boot that is going to kick your sorry ass all the way back to Earth, sweetheart. I am death incarnate, and the last living thing that you're ever going to see. God sent me."
I cheered aloud. Because of what she said, how she said it, and because of who she was. I loved her, and she promised to lie waste to anything in front of her, and I believed her.
Star Trek TNG, the end of Encounter at Farpoint:
Riker:"Just hoping this isn't the usual way our missions will go, sir."
Picard: "Oh no, Number One, I'm sure most will be much more interesting. Let's see what's out there. Engage."
It's not poetry, but the Let's see what's out there got me, and it will always get me. It's far from being the best series I've seen, but I still think it's the one that inspired me the most. Let's see what's out there. Gosh. That got me into many things, fandom being just one of them.
Batman The Animated Series, Nothing to Fear:
I am vengeance! I am the night! I am Batman!
Yes, yes, it's parody material now. But neither Batman nor I had met the Scarecrow before. He had never faced his fears like that. He was panicked, hanging from a zeppelin (and when in BTAS somebody was hanging from a zeppelin, it was as realistic and scary as it should be), and his father was telling him that he was a disgrace.
And then he pulled himself out of his fear and... God. That's Batman for me. Not the one who smirks "I'm Batman" as if it were a cool job. It's the one who yells "I'm Batman" because he has earned it, damned be the world.
Runners up, because the series was *that* good: At the end of "The Cape and Cowl Conspiracy," when Jozek turns around his chair and starts laughing, and he says To wear it. YES. A thousand times. YES. And near the end of "Perchance to Dream", when Bruce is about to kill himself in a forced dream in order to wake up. Mad Hatter: 'What happens if you are wrong?' Bruce: 'Then I'll see you in your nightmares.' That was Bruce, not Batman - and it was Bruce who scared me. Squee.
Mad About You, that moment when it looked like they were about to split up. I didn't cry. Not really. And you have no witnesses.
Angel, Lineage: Wesley's father (well, so we all thought at the moment, including Wesley), has betrayed him, they are in a rooftop standoff and Wes can't quite shoot him to prevent him from stealing an artifact. Then his father begins to speak of taking Fred hostage and walk to her, and Wes just shoots him. And walks over him and keeps shooting until he's out of bullets. Nothing on his face, no hesitation, no words, just bang. Bang. Bang. I sort of screamed at the screen. I'll love Wes forevever.
Firefly, Objects in Space: The camera pulls out and we see River, and she's laughing, and then there's a bit of music and it cuts to commercials and I. *hearts* I probably haven't quite recovered from that.
Justice League: That moment when Question figured things out, and went to kill Luthor, and Luthor knew it all, and was playing with that, and I... the *awe*. That's how you do serial television, dammit. I know the canonical example of masterful continuity is Babylon 5, and it deserves it, but let me tell you: when things clicked in JL, they *clicked*. And you ran for cover, or wanted to.
Seinfield: "Kramer, given the legal oportunity, I will kill you." Shut up. Perfect line, perfect delivery, the ethos of the series in a nutshell.
Southpark: Remember that older kid who kept making a fool of Cartman? Remember what happened to him at the end? The chili? Any wonder that I'm still *flailing* at that?
Cowboy Bebop, Ballad of Fallen Angels: The fight, as fast, vicious (heh) and visceral as the show always did them. The rythm - and then the stalemate, Spike falling through the window and... *boom*.
I loved the whole series, and I'm not sure this is its best moment (Spike's fight against The Fool was *masterful*, and the series used silence and stillness almost as well as it used speed) but, although not the best, it's perfect. I don't know if that makes sense to you, too.