The Mighty Thor/Awesome

When Beta Ray Bill knocks Thor's alter ego Donald Blake unconscious. Looking for the powerful weapon Thor used he finds only a stick. Whacking it against a his ship in anger and exclaiming the curse "Thunder and lightning!" he is surprised to find himself holding a magic hammer that lets him easily defeat some SHIELD agents. (Iss. 337)
Odin, facing down Mjölnir thrown by Beta Ray Thor so hard the air behind it is on fire, catches it in mid air. (Iss. 338)
After Agnar attacks Balder, he has to sit through a 5 page lecture by Volstagg (with Volstagg sitting on him) on why Baldur won't fight him back. He is finally let up and left with some parting words from Volstagg: "Surely if some harm came now to Balder and you were responsible, why I might even find it in my heart, so much larger than that of ordinary men, to forgive you. Why, even Thor or Fandral the Dashing might forgive you because they were once young and daring themselves. But Hogun the Grim? Hogun was never young. He would never forget ... or forgive!" (Iss. 340)
- Cue Hogun right behind Agnar, complete with a look of sheer, pants-wetting terror on Agnar's face.
Baldur, willing to die to protect his oath not to kill, is goaded by Malekith and forced to kill a battallion of demons to fulfill a mission that could save billions of lives. He then proceeds to force Malekith to teleport away and beheads Loki.
- Who then manages to make the scene even more awesome by getting up once Balder leaves and finding his head with all the concern of someone missing a sock.

Loki: "After all, the first thing a sorcerer of quality learns is to make himself as difficult to kill as possible."

Surtur, the ruler of the fiery realm of Muspelheim, destroys a galaxy because he needs the heat to forge a sword.
The final three-issue confrontation in Asgard where Thor, Odin and Loki fight Surtur to keep him from ending the world.

Odin: "For Asgard!"
Thor: "For Midgard!"
Loki: "For myself!"

In the aftermath with Odin missing, some frost giants are spying and think it might be a good time to attack Asgard. Hela comes to claim Odin's spirit for Hel. After administering a vicious beating, Thor yells at her as she flees "Flee, Death! Flee and lick thy wounds, you who are not fit to utter my father's name! And know that Thor shall not be far behind!" The frost giants quickly reconsider their attack plans and opt for a long trip to the mountains.
Thor, under a love spell, walks in to find Loki sleeping with the object of his affections. She has him bow down but teases him too much and his rage offers him a moment of sanity. He throws his hammer up into space and holds Loki by the throat over the balcony until he will release Thor from the spell: "Look you, Loki, to the sky! For there soars the hammer of Thor and by royal Odin's decree, it must return to my hand. Nothing may bar its way! Not even the head of Loki!"
Thor leads an army of Asgardians into Hel to rescue mortal souls held there by Hela. He wrestles Hela for their souls and is winning when she smites him with the hand of glory, mangling his face and sapping the life from him. Hela tries to make him kiss her cape and he rips it from her, robbing her of her power. He forces her to abide by the bargain or he will rip the cape (which he barely has the strength left to do). He grows his beard to hide the scars. (Iss 361)
Hela curses Thor with brittle bones that won't heal and an inability to die. He proceeds to break his arm, some ribs and a hand but creates a suit of Asgardian steel that will hold his body together. He wakes up in Loki's castle and saves him from frost giants. They break in just as the armor materializes around him and don't recognize him so he has to explain himself: "MY sire was ruler of the GODS rash thurse! Odin was my father and the thunder and lightning are my birthright! They speak my name in whispers in the nurseries of thine icy home!"
The giants summon the world serpent (which encircles the entire Earth) who is destined to kill and be killed by Thor at the end of time. Some of the best dialog I have read in a comic ensues in Thor #379 as the world serpent appears in another guise as Fin Fang Foom (complete with underwear!) to find Thor and fails to recognize him due to the armor.
To save the world, Thor unleashes his full power against the world-serpent, knowing it will break every bone in his body, forcing him to live in torment until Hela lets him die. Thor: "You are a mighty fighter, but in the end, you are only a selfish creature while heroes... heroes have an infinite capacity for stupidity! Thus are legends born!"
- I can't believe it has yet to be mentioned that the entire issue with Thor versus Jormungandr, aside from the dialogue, is written as and in the style of classical Old Norse skaldic poetry. And it is amazing.

Nine steps the hero takes striding as a giant

As giants are taking out their frustrations on the immobile form of Thor's armor filled with his undying jellied body, Loki summons the Destroyer, the ultimate weapon created by Odin to fight the Celestials, who has been a melted pile of slag in the Andes for years. After using the life force of one giant to kill all the others, the Destroyer tries to kill Thor but cannot because of Hela's curse. The Destroyer enters the spirit realm to claim this indestructible life force which will make him invincible, but fails to recognize the being as Thor, who had beaten the Destroyer there before. As the spirit Destroyer tries to run away and screams "NO!!!", spirit Thor grabs him and says that only one will leave alive. Back in the real world the Destroyer puts on Thor's cape, belt and head feathers, picks up Mjölnir and teleports away. (Iss 381)
- To reiterate: The Destroyer's reaction when he finds out his foe is Thor is absolute terror.
Thor, in the Destroyer's body, lays waste to Hel with ease. (Iss 382)
Thor drops by for a friendly chat with Loki about all the trouble he caused Thor and Asgard lately. Thor nonchalantly breaks Loki's arm with Mjölnir as a reminder "Only Odin's forebearance was infinite!"
- And then flies merrily off, musing about how visiting his brother always cheers him up, and he should do it more often. Sucks to be Loki, heh.
As you might be picking up, when he is written right, Thor is a walking Crowning Moment of Awesome.
- Looks like I found a new summer project.
The Last Stand of Skurge the Executioner, holding the bridge at Gjallerbru in the underworld, dual-wielding M-16s against an onrushing horde of the dead. "He stood alone at Gjallerbru. And that answer is enough."
- Two decades later in Thor: God-Size, they established that bringing Skurge back to life would destroy the entire Marvel multiverse in a story that was just as manly, just as epic, and just as much of a Tear Jerker.
- And from that same run but on the other end of the spectrum, we have the time Thor hit a serpent the size of a small state so hard that it breaks every bone in both of their bodies. The explosion was so big the sound effect had seventeen Os.
In one of the earliest stories, Thor vs the Carbon Copy Man, Thor is against an alien that can change forms to anything. So said alien makes himself invisible, and whales on Thor with an iron fist. Thor, cunning bastard he is, makes rain, and finds his adversary. After knocking him out in one blow, Thor wraps him up in a metal net. And then throws him OUT OF THE SOLAR SYSTEM!
That line he gives to Ultron... you know the one.
In the Journey into Mystery Fear Itself arc, Loki has been unveiling tiny, tiny pieces of his plan. Then the Serpent summons Dark Asgard, a copy of the real thing, hovering over New York that the Serpent will use to control the real Asgard. Loki comments that he has a plan. Cue Loki grinning and sitting on the shoulder of the Destroyer Armor [1].
- Heck, it's just great to see that the armor's finally going to be used against a bad guy instead of Thor!
The Hammer And the Holocaust! (Thor 127, April 1966): Stripped of half his powers then beaten to a bloody pulp by Hercules, Thor still manages to single-handedly save Asgard from usurper Seidring The Merciless. As Thor collapses near death at the foot of the Odinsword (yes, it was that close), The Old Man finally admits: "Thou art the noblest Asgardian of all."
Three issues later, a newly recovered Thor takes down the entire frigging Netherworld in a battle for Hercules' soul. When Thor finally emerges victorious, the Son of Zeus proclaims him the greatest warrior he hath "e'er known," swearing friendship until his dying breath.
Shall Earth Endure? (FF 243, 1982): While the Fantastic Four helplessly watch Galactus prepare to nuke the whole damned planet, a Sound of Thunder splits the heavens: "I SAY THEE NAY!!" The cavalry has arrived, and their hero has a hammer!
Meeting Iron Man again after Civil War and proceeding to curb stomp him before telling him the reason Tony's been able to take him on before was because he was holding back, and then lecturing him on just who he is, what that means and about the incidents in Civil War. It's worth mentioning that Iron Man initiated the confrontation and believed he was fully prepared to deal with him. Thor took him down with one hit. OWNED!
In Journey Into Mystery, Kid!Loki is in a nightmare. The narration boxes continue describing him in a worse and worse manner, worse possibly than even his old villainous self deserved, as Loki begins to get depressed...only for Loki to declare that this is his dream and grab the narration boxes and rip them to pieces.
- Also later tricking Nightmare into holding still long enough for Daimon Hellstrom to show up.
Everything Loki does under the pen of J. Michael Straczynski or Kieron Gillen is a Crowning Moment of Awesome. His plans are built slowly, but to perfection, and they haven't failed yet.
Journey Into Mystery #106 involves Mr. Hyde ambushing Thor after the thunder god saves a coliseum full of innocent people from him and the Cobra. Fed up with being jerked around by Hyde and disgusted by Hyde's threatening so many innocent bystanders, Thor decides to settle with him once and for all. Thor does so by deliberately dropping Mjolnir, saying that if he can't defeat Hyde within sixty seconds he doesn't deserve his powers. Thor then pulverizes Hyde in a vicious Curb Stomp Battle, beating him down with his bare hands and leaving him unconscious for the police, all within less than a minute.
Eilif the Lost, last survivor of a Viking colony in Antarctica, made a Heroic Sacrifice to save Thor (and New York City) from a huge dragon that'd shrugged off everything Thor threw at it. And then it got MORE awesome, as Thor gave him a Viking's funeral, with the dragon's corpse at his feet, calling down lightning to ignite the funeral pyre of "No longer Eilif the Lost, but Eilif Dragonslayer!" The awesomeness didn't end there, either. Not one but at least three Valkyries -- and Odin himself -- showed up to "welcome the last Viking ... into Valhalla!"