Secret Wars #4: Dr. Doom and the villains manage to destroy the heroes' base. The heroes retreat and Molecule Man, normally unaggressive compared to the others, gets his crowning moment when he decides to deliver a finishing blow by dropping an entire mountain range on them telekinetically. The Hulk gets his own crowning moment of awesome by catching the mountain and bracing it just enough to keep the heroes from getting smooshed. The cover featured the caption: "Beneath One Hundred and Fifty Billion Tons Stands the Hulk. And He's Not Happy!" Mr. Fantastic follows up with his own crowning moment of awesome. He quickly modifies Iron Man's armor and jury rigs two power cables by cannibalizing Hawkeye's arrows and Spider-Man's web shooters while commenting on the genius of each. When the Hulk registers his annoyance:
Mr. Fantastic: I see. Well, that's exactly the kind of self pitying mewling we've come to expect from you, Hulk. You're correct; you are a brute! So keep using your muscle! That's all you're good for!
It's worth noting that after their escape, Reed explains that he was intentionally goading the Hulk, since the Hulk's strength increases the angrier he gets. Hulk himself realizes this afterwards.
Later, after the heroes survive a fight with Galactus, Doctor Octopus leads a sortie and pronounces them easy pickings. Bulldozer replies "If that mountain didn't finish them off no way are they ever easy pickings!"
While the rest of the heroes are under the mountain range, Thor takes on the entire bad guy team and, if not for the presence of Ultron (and Molecule Man, probably, though he didn't take part in the fight), may well have defeated all of them.
Spider-Man completely beating the crap out of the X-Men, including Colossus, Nightcrawler, Cyclops and freaking WOLVERINE HIMSELF! Sadly, Professor X made sure he'll never remember it.
Nightcrawler: "His strength—! His speed—! Unbelievable! He is AWESOME!"
Titania's pretty badass herself, though, when she picks up a fifty-foot piece of metal junk and throws it at the fleeing heroes, who are five miles away.
Pointed up by the Wrecking Crew who also throw junk... smaller ones.
And perhaps the crowning moment of awesome for Secret Wars is when Doctor Doom defeats and steals the power of the Beyonder, the godlike being who is the cause of the entire Secret Wars story.
That warrants a bit more exposition. Doom, after stealing Galactus' powers first when the Big G attempts to devour Battleworld, goes up against Beyonder. But seeing as the Beyonder was powerful enough to consider Galactus a gnat and move him to Battleworld to begin with, he fails miserably. He pleads to the heroes to aid him in his hour of need, lending him their power. They all refuse, and Doom gets brought down. The Beyonder, an eternally curious being, wonders what manner a creature Doom is and how he managed to do what he did. He starts dissecting him alive, limbs get removed and armor and skin and flesh slowly float away from Doom. In his last waking moment, Doom decides that this will not happen to him, he is DOOM. And manages to activate the device in his chestplate, and drains the Beyonder's power into himself. Talk about awesome
For most villains, successfully stealing/duplicating the power of frikkin' Galactus would be considered the capstone of their careers. For Doom, it was step one in a master plan by which he would successfully hijack nigh-total omnipotence. And remember, this was before the Beyonder was retconned to not actually be such.
Not Doom's only moment. After Doom has taken the Beyonder's power and told the heroes that he carries no grudge against them and just wants to do his own thing with his new omnipotence, the heroes debate on whether they can and should take on someone that can annihilate them in an instant. When the last of them, Colossus, agrees to fight back, Doom annihilates them all in an instant with a 'bolt from the blue'. Hot damn.
Galactus himself has a subtle moment of awesome in his own actions. Rather than playing the Beyonder's game, he attacks directly. This is to keep him out of the majority of the story, as once he gets up again and starts taking action, everyone has to drop what they're doing to deal with him, even though they can only guess and they can't risk doing nothing. As Nightcrawler puts it:
Nightcrawler: Galactus's bluff is better than a handful of aces, eh herr professor?
Last to earn a moment of awesome is good o'l Captain America. Doom, who's being subconsciously sabotaged by a remainder of the Beyonder's power slays the star spangled Avenger as soon as he bursts through to his inner sanctum. But Cap 'reforms', and goes for Doom again. Despite being blown to smithereens 'every time' Cap mysteriously comes back, Doom goes insane, and loses the power of the Beyonder, who had been inhabiting Klaw, all this time.
In other words, Captain America refusing to stay dead aids in putting down Doom.
Wasp allying the Lizard to herself with her compassion
Captain America's shield is nearly destroyed in the fighting and, as noted, cannot be reforged; its construction was pure accident. What does he do? He finds every single piece of his shield, lays them out on a table, and reforges it anew from sheer willpower alone. Get this man a Green Lantern ring.
A meta one in that the event actually manages to have a story arc for every character involved, making everyone seem necessary to the plot. This is something that most comic book events cannot do.
Secret Wars 2
The Beyonder strips himself of his power to see what being a human is like. Mephisto is watching and attacks and there's nothing the Beyonder can do because he is a normal human. Then he remembers that he just has to not believe in Mephisto and there's no way Mephisto can hurt him.