When Lady Kycilia assassinates Gihren Zabi in "Space Fortress: A Baoa Qu", showing just who is going to be the last Zabi standing. After so many drawn out, bombastic space battles, seeing a Smug Snake go out with a well-deserved gunshot to the head is pretty damn satisfying. Kycilia's chilling I Did What I Had to Do speech is rather epic as well, showing that patricide is not cool in Zeon.
"Get rid of the body! Even a supreme commander can't get away with the assassination of his own father. If any of you disagree, then file charges against me after the battle's over!"
"You doubt that I'd kill you? You should know it's a family tradition."
This is made even more epic by the reaction of the bridge crew: after a few moments, one of them notes that the battlecarrier Dolos has just been destroyed and broadcasts that Gihren was on that ship, with nobody telling the truth. Everybody agreed with her.
The Battle Of Odessa, in which Amuro downs two Zeon aces before capping it off by disarming a nuclear missile in midair. It's said that after this, the White Base crew met General Revil 'on friendly terms'. No shit.
That battle is also awesome for the Federation conventional forces, as it makes clear that not only a tank can still destroy an unwary mobile suit's ass, but also that Zeon only got so far with invading Earth only because the Federation's ground forces had been neglected before the war and had to be rebuilt from scratch, without the contribution of the whole of North America, large part of the European side of the former Soviet Union and most of China's immense industrial power.
The White Base kids, none of whom are over seven, put their time aboard their ship to good use in "A Dream Of War Orphans", in which they mount a remarkably competent bomb-disposal operation. Particular props go to five-year-old Letz Cofan, who organises the whole thing and even hijacks a flatbed truck to take the bombs away from the Federation's vital GM factory.
"Farewell in Side Six" marks the point when Amuro truly graduates to One-Man Army status, taking out nine Rick Doms in less than three minutes. For the record, a pilot is considered an ace after they've downed five suits in their entire career, let alone a single battle.
The Bright Slap moment, especially in the movie. Bright's words are powerful and his slap even more, turning wimpy Amuro into someone who takes responsibility for his action because he's a man.
Amuro: Y... you hit me!
Bright: So what if I hit you? You can't be a man if you can't take hits!
Amuro: That's twice! Not even my dad hits me!
Bright: Then maybe your dad was too soft on you!
Ramba Ral's first battle with Amuro in his Gouf. "This is no Zaku boy. No Zaku!"
In the final episode, after Char and Amuro disable each other's mobile suits (which was also awesome), Char lures Amuro into an armory and baits him into a Sword Fight, taunting him that his piloting skills and Newtype powers wouldn't help him. They then proceed to get into a Single-Stroke Battle: Char stabs Amuro in the shoulder...Amuro stabs Char in the forehead, the latter being saved only by that ridiculous mask. His spacesuit from his girlfriend helps too.
Then Char gets his own back in his last scene of the show, where he braves a Collapsing Lair to deliver final vengeance for his father in a manner most awesome - namely, by nailing Kycilia in the face with a bazooka. From the other side of her battleship, from a considerable distance away, through the battleship's front window, while flying on a jetpack and while said battleship was rapidly ascending on an escape course with said Zeon station rapidly falling apart around him. Char bet it all on a long shot and won despite the odds. Hot damn.
Char for how he handled his best friend, another Zabi. A normal bastard will leads his best friend right into an enemy trap. A Magnificent Bastard? Calls him on the phone, explains his motives, and waves good-bye.
"Take your sorrow, and turn it into anger! Zeon thirsts for the strength of its people! SIEG ZEON!" Big BadGihren Zabi taking the death of his little brother and turning it into a political rally; not in the final episode, but still an iconic moment for the series.
Gihren gets a good run of moments during the opening scenes of the penultimate episode, "Space Fortress: A Baoa Qu". Desperate to stop his father from reaching a peace accord, Gihren decides that if you're going to cross the Moral Event Horizon, you might as well go big or go home and opens fire with the Solar Ray, wiping out Degwin, General Revil, and half the Federation fleet. He than proceeds to launch into yet another Rousing Speech, lecturing the troops on how they are the Master Race, and urging them to annihilate their enemies. Totally evil? Yes. Totally awesome? Also yes. It's an iconic enough speech that it's used as the background narration in most commercials for the series.
In a quieter way, the above is also a CMOA for Degwin Zabi, who finally finds his backbone and stands up to Gihren. While it gets him killed, it also forces Gihren to fire the Solar Ray early, setting in motion his ultimate defeat. Let's hear it for old man Zabi.
Dozle Zabi gets a pair of them in the same episode. The Zeon are losing their massive battle against the Federation at the asteroid base Solomon. So, in order to give almost everyone time to retreat, Dozle takes an incomplete mobile armor into action - the Big Zam. Piloting this on his own, Dozle is essentially able to decimate the Federal Forces until, of course, our main character shows up. Still, Dozle essentially holds off an entire army on his own - and it takes a Heroic Sacrifice to even make the mobile armor vulnerable to damage.
The second one? After Amuro disables the Big Zam, Dozle still hasn't given up. He picks up a machine gun, steps out of the Big Zam and starts shooting at the Gundam.
And to drive it even further, Dozle's determination gets embodied by a demonic spirit creepy enough that Amuro practically craps his pants.
Even the wimp CameronBloom gets a genuine CMOA when he tries to atone for his cowardice by using his personal shuttle as escort for the White Base during a battle. Even Big Brother Mentor Sleggar, who once hit him for disrespecting Mirai's feelings, had to recognize the guy had grown some balls
How could you guys forget the battle at Side 6? A damaged White Base is being pursued out of a neutral colony by two Zeon battleships. Right after passing the neutral perimeter and into no-man's space, Bright chooses to engage the enemy which is still inside of the neutral zone and cannot fire back. The result? White Base utterly destroys the enemy with Amuro single-handedly shooting down 9 out of 12 enemy Rick Dom suits and downing a battleship. All in the matter of three minutes.
Not actually in the series proper, but General Revil's "Zeon is exhausted!" speech. With the Federation on the brink of total surrender after Zeon's opening blitz, he escapes from captivity and broadcasts his speech exhorting the Federation to fight on. The full text of the speech appears in the novels.
Bonus point for Revil passingly tearing into the Federation's own corrupt government before dismantling the idea it could justify Zeon's war crimes.
Later made more magnificent when M'Quve decides to deal personally with the White Base and cripples the ship with a nearly identical plan, that succeeded because M'Quve, being the supreme commander of Zeon's forces on Earth, has access to much better equipment, like plastic jetpacks that the White Base didn't detect (allowing his men to jump on the White Base without setting off the metal sensors) and remote controlled bombs (the one thing that would have allowed the soldiers to blow up the Gundam).
Char's debut in combat. The Gundam is an extremely powerful MS that easily took down two Zakus with the pilot still trying to learn how to move it. When Char shows up, Amuro knows how to make it actually fight decently... And Char utterly and completely kicked his ass. The Gundam would have not survived the battle, had Char suspected about the Nigh Invulnerable lunar titanium armour and brought the heat hawk.
And even with the heat hawk, Amuro barely survived. How is it even possible, if Char's weapons couldn't even scratch the Gundam's armour? Easy: Char started kicking the Gundam in the 'belly' with enough strength to throw Amuro around the cockpit. Without the seatbelts, Amuro would have died at the first kick... And those poor seatbelts took a lot of abuse by the time Char was driven off.
The source of Char's status as The Dreaded: in the epic Battle of Loum, that allowed Zeon to conquer supremacy in space, Char became an ace by taking down five battleships. Not five fighters or five mobile suits, five battleships, single-handedly dodging the point defence (even if it was made easier by the Minovsky particles jamming the radars, a Magellan-class battleship still has 14 anti-aircraft turrets, and he dodged those alone for five times) and taking down the most massive battleships of the Federation. Plus, his fame in doing this in spite of Shin Matsunaga taking down six ships in the same battle implies he did it alone (Matsunaga is canonically known for having been part of a team at Loum).
He caps this in the final episode, by taking down the Zanzibar-class mobile cruiser Chimera with a man-sized bazooka. The best part is that it was by accident: he was just decapitating Kycilia with the bazooka, and the shot happened to wreck the piloting systems and kill everyone on the bridge, sending the ship to crash.