This exchange between Agent Simmons and Captain Lennox:
Simmons: "I'm gonna to count to five." Lennox: *shoves gun against Agent's chest* "I'm gonna to count to three."
Captain Lennox is pretty cool throughout the movie, but his CMoA is definitely during the final battle, where he charges Blackout on a motorcycle at high speed, jumps off the motorcycle and slides under Blackout to deliver a point-blank shot with a grenade launcher.
The fact that Shia LaBeouf as Sam improvised most of his rant about how the Autobots were messing up the backyard, and Peter Cullen, recording his lines in some studio miles away, goes 'Calm down, calm down' in perfect comedic timing.
Probably the moment when you realize just how insane the fights were going to be was the first robot confrontation between Bumblebee and Barracade. Bumblebee stands protecting Sam and Mikaela and Barricade leaps forward like a predatory animal and kicks Bumblebee in the face, sending him flying into the distance. Bumblebee looks up, shakes it off and rolls back to his feet and returns the favor in one swift motion.
Made even better when Sam and Mikaela are driving away in the unhurt Bumblebee— and Barricade is lying on his back as mostly twisted wreckage. Bumblebee is a FEROCIOUS animal when Sam is in danger.
Ironhide using his cannons to propel himself in the air and somersaulting in mid-air. And that was before dodging missiles from Brawl, while transforming.
Another one goes to Ratchet who uses a buzzsaw. to cut off one of Brawl's arms.
How about when the Sector Seven agents are taking the kids away, and suddenly their car is lifted several feet into the air by a 30 foot pissed off robot? While the agents can just stare up at Optimus, Prime delivers a line that would make a sane man shit himself: "Taking the children was a bad move.... Autobots, relieve them of their weapons." Prime scorning these humans who had moments before been total dicks, followed by Jazz using a massive magnet to hijack all of the Agent's weapons and reducing them to being nothing more than fleshy slag, is quite endearing.
Sam Witwicky: I'd like to introduce my friend, Optimus Prime.
The F-22 attack on Megatron stands as one for the US military. He had been in an even fight with Optimus Prime, but a single salvo of human missiles brought him to his knees.
Starscream taking on several F-22s, seamlessly shifting between his jet and robot form, and destroying about half of them before hiding among them and seemingly taking part in the attack on Megatron.
The U.S. military gets one early in the movie with their coordinated ground forces, A-10, and AC-130, forcing Scorponok to actually retreat, leaving a piece of itself behind.
The villagers get one too. They could have been hostile to the U.S Special Forces team, and they wouldn't have been unjustified in feeling that they brought Scorponok to them. Instead, they start grabbing bolt action rifles and revolvers and fight alongside Lennox and his team despite their own comparatively pitiful firepower.
Transformers: Dark of the Moon (2011)
In a recent TV spot we are treated to this line by Optimus Prime:
During the battle with the Dreads, Dino/Mirage uses cables to attach to Hatchet and literally road skis across the road behind the Decepticon.
Megatron's total trashing of Sentinel just as Sentinel is about to kill Prime.
Wheelie and Brains, the two smallest Autobots in the film, manage to hotwire an entire Decepticon cruiser
Optimus' slaying of Megatron consists of him jabbing his energon axe into Megatron's skull and pulling out both Megatron's head and spine from his body with one arm.
Megatron: "Who would you be without me, Prime?"
Optimus: "Time to find out."
At first, it seemed a tad strange that Optimus would execute Megatron so brutally even though Megatron was talking about a truce. Then it struck me that Optimus was likely venting three movies worth of rage on Megatron for his murderous ways (including killing Jazz and however many hundreds of thousands of humans killed in ROTF and DOTM). That made it seem more badass, as Optimus likely knew Megatron would never change, and deserved what he was about to get.
Also a bit of Fridge Brilliance, Megatron offered Prime a truce (in essence, a deal; work together, kill Sentinel, and then (most likely) go their separate ways for the moment). If Optimus had accepted Megatron's offer and worked with him (doing what Sentinel did- work with Megatron as a means to an end (in this case, killing Sentinel), how could Optimus have been any better than his (former) mentor?
In all honesty, the "truce" didn't sound genuine at all. Megatron said he wanted to be in charge again and his "who would you be without me?" line just added to the mockery. After all this warlord has done, there's no truce to be had. The world would only know peace when his spark was extinguished and Optimus saw to it.
Ironhide's arrival into that fight was a CMOA in itself. He comes tearing in at full-speed in truck mode, rams both Decepticons in a head-on collision which causes him to flip over them, transforms to robot mode in mid-air, and lands on his feet with both guns already drawn and cocked at the Decepticons' heads.
To save everyone the trouble...because we'd be hear all day listing this...but pretty much ANYTHING Bumblebee and Optimus did!
Colonel Lennox and a strike team of about twenty or so humans, working together without any vehicle or Autobot support, take down Shockwave (though it takes the Autobots and Optimus to actually defeat him), Barricade, and four other Decepticons on foot, using nothing but accurate sniper fire, parachutes, and sheer balls.
Not pictured on-screen; several years of refining their tactics by fighting Decepticons. Think of all the bullets fired, blood shed, and lives lost.
For those who haven't seen it and wished to be spoiled, Sam knocks Dylan Gould into the Space Bridge Pillar (electrocuting and killing him) with an iron pipe he picked up off the ground after saying this! It was, pretty much, Sam's response to Gould, who was basically giving him a Hannibal Lecture, "You think you're some kind of hero?" To which Sam replies with the above quote.
Optimus Prime. Buzz Aldrin. Meeting one another and, with the utmost humility and sincerity, saying that it is an honor.
Optimus Prime finally defeating Megatron for good.
Prime's trailer. We've been waiting for it for two films and it doesn't disappoint. Not only does it turn into a badass flying harness, but, like the original, it opens up into a base... which is fully stocked with dozens of weapons.
Starscream's back to being dangerous in DotM. He drops down from low orbit to shoot down the Autobots' spaceship and later leaps off a building and shreds the Ospreys transporting Lennox's team with his buzzsaw hand. Also serves as a Call Back to his F-22 Stepping Stones in the Sky moment in the first film.
Bumblebee killing Soundwave. He overpowers Soundwave and his Mooks, then jams his arm cannon into Soundwave's chest and blows his head off through his chest! Made even better due to the fact Bumblebee is shown mourning the death of Wheeljack at Soundwaves hands and now has avenged his fallen friend.
The novelization adds a little one for Ironhide. Whereas the film had him & Sideswipe engaging the two remaining Dreads in a gunfight, the novel has five Dreads charging at the NEST base. Ironhide simply transformers, stands in their path, and becomes The Immovable Object, letting the 'Cons literally crash into him. Each of the Dreads is killed on impact, while Ironhide simply withstands the hits with little more than some scratches and being knocked back a bit. He then casually brushes Decepti-parts off of himself and quips "They just don't make them like they used to".
When the Autobots return for the final battle after having been thought destroyed with their ship, Optimus delivers what may be the single most badass line in the entire franchise:
Optimus: We will kill them all.
It's the way he says it more than anything.
The novel also adds a Dying Moment of Awesome for The Twins. Skids dives in front of a shot fired by Sentinel Prime at Bumblebee, saving Bee's life at the cost of his own. This causes Mudflap to fly into an Unstoppable Rage and charge Sentinel, dodging the traitorbot's shots, tackling him to the ground, and pummeling him as hard as possible. It does little harm to Sentinel, but it does give the others time to escape, and as Sentinel blasts him, Mudflap continues to attack him relentlessly even as he is literally disintegrating. Sentinel even mentions that Mudflap died a death worthy of an Autobot.
Basically anything the Wreckers do in the final battle. Really, there's no way that a trio of weaponized race cars tearing down the streets blowing up everything in their path can't be insanely cool.
Three words: "Wreckers...kill him!". The sheer brutality that the trio proceeds to unleash upon the pilot of the downed Decepticon fighter is practically a whole brand of badass unto itself.
Lennox and his team get his fair share of awesome in the movie.
Lennox: Listen up! If we wanna hit back, we're gonna have to wingsuit in. It's the only way to get close. I can't promise anyone a ride home, but if you're with me... The world needs you now. Soldier: [steps forward]...I'llfind my own ride home,sir. Lennox: [nods appreciatively] WHO ELSE? [The rest of the soldiers step up and shout their commitment to the mission]
Sentinel basically duels Optimus, while being shot at by NEST soldiers, and while smacking away the other 7 Autobots whenever they try to interfere. In short he fights all the good guys at once by himself and hold his own. It ends with a CMOA for some random unnamed NEST soldier, who pegs Sentinel with a rocket just a he finally pulls out the dreaded rust gun he was able to kill Ironhide with, causing Sentinel to lose his gun, and for him to fall back. Optimus pursues however and the Awesome goes back to Sentinel, who, one on one beats Optimus in a duel and would have basically won without Megatron suddenly interfering.
Upon rewatching the movie, I found that Optimus has a very efficient way of dispatching foes that works out quite awesomely. He uses said tactic to kill Shockwave and Megatron with deadly efficiency. Both Shockwave and Megatron fire at Optimus as he moves towards them. Optimus dodges both moves and hits his opponent in the chest (with a gunshot in Shockwave's case and his axe in Megatron's) which stuns them momentarily. He then uses that opening to deliver the set-up blows (punching out part of Shockwave's torso then slugging him in the face and choke slamming him or kicking out Megatron's knee from behind) and then delivers the killing blow. It's quite awesome to see the tactic play out.
The humans launching a Macross Missile Massacre against the Deceipticons from far enough way that it takes the better part of a full minute to show the missiles' flight into the city, opening up the battle proper.
Dreamwave Transformers comics
In a Transformers vs. G.I. Joe comic set in World War II, Grimlock and Roadblock are hanging onto a cliff, and Grimlock is starting to slip. He tries to get Roadblock to save himself, that he'd try to hold on long enough for him to get up, but Roadblock refuses:
"Did you say TRY? We don't try around here, soldier — do you hear me? We don't try, and we don't quit! NOW REACH!GRAB THAT DIRT! You are a lean, mean, climbing machine, and you are going nowhere but up! Sound off! I want to hear you say it — 'Me, Grimlock, going up!'"
In the second Generation 1 mini-series, Ultra Magnus takes down Menasor while still in truck mode. He does this by hurling insults to each of the Stunticons that make the Combiner. This drives Menasor insane and allows Ultra Magnus to catch air and ram Menasor IN THE FACE.
IDW Transformers comics
Another one for Hot Rod/Rodimus, this one from the IDW comics. Hot Rod has been tormented for years by the slaughter of his team while obtaining the Magnificence, a font of infinite knowledge. He does not know that his team was betrayed by Dealer, a Decepticon mole. Dealer finally finds a way to convince Hot Rod to lead him to the Magnificence, with himself in tow. As they approach it, Hot Rod wonders aloud how the Decepticons intercepted his team, how their mission was sabotaged, and why Dealer was captured but the others were killed. His first question to the omniscient 8-ball of the stars? "Did Dealer betray us?" "Yes!" Cue Hot Rod shooting Dealer's head off.
In Spotlight: Metroplex, Sixshot hunts the Throttlebots through (unbeknownst to him) Metroplex's alleyways. Just as he's about to kill off one of the Throttlebots for good, Metroplex pops his arm out and pounds Sixshot full-force into the ground with his fist. And then Sixshot stands up again. So Metroplex transforms into his ridiculously gigantic robot mode and steps on Sixshot. (In a splash panel spanning two entire pages, no less.) At the end of the issue we see that Sixshot is still alive and moving after all that, albeit quite crushed and mangled. Really it's a case of both the good and bad guy getting a moment of awesome at the same time.