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)
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 forging of Twilight is a CMOA of its own. For an entire year, Simonson had one page per issue of the forging, with each strike producing a massive "DOOM!".
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!"
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
The entire issue is done in splash pages. Also, did we mention that Jormungandr is the size of New Jersey? And Thor gets swallowed and gets free by flying out through his teeth?!
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.
All of the above come from Walt Simonson's time on the comic. There's a reason many fans consider it not just the best run of Thor, but the best run of any title ever.
Simonson wrote, drew and inked the first two and a half years of the title, along with #380 (the aforementioned all double-page-spread issue). He would've drawn more had he not taken on other titles at the time. There were only two writer fill-ins during his tenure.
When Comic Book Resources ran a "Greatest Thor Stories Ever Told" contest, six of the winning choices were by Simonson... including the entire top five. The only other writer close to achieving such domination in one of those contests was Larry Hama, who took nine out of ten slots on the Greatest G.I. Joe Stories contest. Keep in mind that Hama has written about 75 percent of all G.I. Joe stories ever published, while Simonson's run was only about fifty issues in the title of one of Marvel's major characters.
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.
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.
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.
Later on, at the very start of Invincible Iron Man, Thor and Iron Man meet at the funeral of a group of super-heroes. When they confront each other, Thor very lightly taps Iron Man's armor... and cracks it. This was the Extremis Armor, which at the time was arguably the strongest conventional armor Tony had ever fielded.
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 Mjölnir, 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.
In the latest series of Thor books, the Thunder God himself is teaming up with his future Old Father self to face off and finally destroy the 'God Killer'. However...the main point of awesome recently is Thor's younger self, back in Viking Times: he manages to face Apocalypse of all people, survives...and...later beats him and mortally wounds him with his axe despite his father's wishes!
In Siege #2, Norman Osborn sends Daken and a team of H.A.M.M.E.R. soldiers into Braxton to find a battered and supposedly defenseless Thor. And they find him, and in one panel he blasts the H.A.M.M.E.R. soldiers and Daken, leaving Daken a severely burnt, smoking corpse before making a Badass Boast.
Thor: I will not run from you Osborn, nor your minions. I will not hide. I will defend my home, and the home of my father... with my very last breath.
From the 70s: the Absorbing Man is giving Thor a really tough fight since he touched Mjölnir. Thor turns and runs into a store with Absorbing Man following him and cornering him. Thor has had enough fighting so he hands his hammer over which Absorbing takes gleeful and then decks Thor only for his hand to get painfully squashed and then knocked out by one punch. The store they're in? A toy store and Absorbing Man had unwittingly absorbed the powers of a cheap cardboard Mjölnir.
Asgardians vs. Frost Giants in Norway. Frost Giants enter, freezing over a whole town. Then suddenly, the Asgardians beam down on Bifröst, and the two massive armies size each other up. Then they charge.
Thor, despite not having his powers & being unaware that he needs to prove himself worthy of holding Mjölnir once again, refuses to leave Sif & the Warriors Three to fight the Destroyer to their deaths whilst he flees with Jane. Hell, he even walks up to the damn thing to try & talk Loki down.
Also a Tearjerker with his speech to Loki. Thor's just so hurt and confused that his brother is doing this, and he seems to think that it's his fault.
At the same time; Jane, Selvig & Darcy's lack of hesitation in deciding that if Thor's staying, so are they.
Sif and the Destroyer have a combined one. First, Sif jumps down and impales the Destroyer through its open face plate just as it's about to fry Volstagg. This is cool enough... but then, the Destroyer reverses its entire body so that it can pull itself up off the spear and take on Sif immediately. It literally rotates around the various grooves on its body.
Volstagg gets one in a deleted scene. After scenting food from at least a block away, he tracks it to two SHIELD agents who are spying on Thor and the others, sneaks up behind them, knocks them out and steals the food in question as he goes. Pretty stealthy for a guy his size.
Thor rampaging his way through the S.H.I.E.L.D. crash site to get to Mjölnir is awesome in and of itself. He goes through the fence, beats up some guys and steals a jacket. Then he goes inside and just beats the crap out of anyone who gets in his way and makes it to Mjölnir. Okay, one guy just beat the ever-loving crap out of a full squad of S.H.I.E.L.D. operatives. That's awesome, but he did it without killinganyone. Thor is a Blood Knight and a Boisterous Bruiser. but he's still The Hero. He just has a lesson to learn.
Loki's best moment in the film: "And your death came by the son of Odin." His other schemes get pretty messed up, but luring the frost giant king into Asgard just to get him into a place where he can be killed is a truly magnificent use of his trickster skills, and you get the sense that's a genuinely sincere moment where he's trying to prove he's fighting for Asgard and his adopted family despite having just found out his heritage.
Realizing that Loki's "There's nothing you can do without defying father" was not at all a slip of the tongue.
Loki stands between a frost giant and a long fall. Loki has a scared look on his face as the giant charges towards him... only to pass right through him and fall to his death. Loki pokes his head out from behind a pillar, and turns off his illusion with a smirk.
Loki freezes Heimdall, not even flinching as his sword inches closer to his neck.
Loki's final scene. He survived being flung into the depths of the universe and drifting through the closing remnants of the Bifröst, to land on earth and begin to investigate what looks like the cosmic cube.
In The Avengers, it appears he didn't actually end up on Earth. Instead it seems he ended up wherever the Tesseract is connected to, and manipulated Selvig through it.
Thor neutralizing Loki by putting the hammer on his chest. And then destroying the Bifröst.
The ends credits sequence, which reveals the path from Earth to Asgard through Yggdrasil while Awesome Music plays.