Paul's Shut Up, Hannibal! to Mohiam, announcing that he's become everything she wanted for her prophecy, but he's not going to play by her script anymore. "Look into that place you dare not look. You'll find me staring back at you!"
In Dune, the entire Fremen populace gets this when you learn that they use gigantic sandworms (up to several hundred meters kilometres long) as passenger transports.
"They fought well."
Thufir Hawat witnsses one: first six Fremen take over an ornithopter, then one of the Fremen crashes the thing into a troop transport in a suicide run.
On a related note, the Fremen get another CMOA when the elite Imperial Sardaukar attack a sietch populated entirely by women and children, and containing Paul Muad'dib's sister Alia. The Sardaukar get their asses handed to them by said women and children, and only manage to escape by turning the exhaust of their transports' jet engines into makeshift flamethrowers. They do manage to capture Alia, but only because she wanted them to. She then scares the shit out of ole' Harkonnen's Bene Gesserit advisor, then kills him with a poisoned needle. CMOA for Alia as well.
"Yes, the guns are interesting. We captured one, for study." There were Sardaukar at every gun, thought Thufir Hawat (who's already one of the deadliest men in the Empire). This man speaks casually of losing only three men to Sardaukar!
Paul Atreides gets his early on when he successfully pilots an ornithopter through an Arrakis sandstorm (which, keep in mind, have winds capable of reaching up to 500 mph and carry sand with enough force to shred metal), while reciting the Bene Gesserit Litany Against Fear.
And just afterwards: "Him against Jamis and not a mark on him!" Even Stilgar was impressed that a fifteen-year-old kid could take on a seasoned Fremen fighter and win — never having killed in single combat before.
Paul Atreides just has moment after moment once he becomes the Kwisatz Haderach.
"It is not necessary for her to convert the water."
"You will think back to the gentle ways of the Sardaukar!" — when speaking of the Emperor's fanatic-soldiers trained in the uttermost ruthlessness and feared throughout the universe.
"How would you like to live billions upon billions of lives? There's a fabric of legends for you! Think of all those experiences, the wisdom they'd bring. But wisdom tempers love, doesn't it? And it puts a new shape on hate. How can you tell what's ruthless unless you've plumbed the depths of both cruelty and kindness? You should fear me, Mother. I am the Kwisatz Haderach."
"Try your tricks on me, old witch. Where's your gom jabbar? Try looking into that place where you dare not look! You'll find me there staring out at you!"
We can thus conclude that the Kwisatz Haderach is a Crowning Moment of Awesome for all humanity.
Wellington Yueh gets one, when he completes his deal with Baron Harkonnen, only for the latter to reveal that he would "release" Yueh's wife by killing her - "You think I did not know... what I bought... for my Wanna?"
Hell, just Paul's first few scenes, where he defies reader expectations and isn't impressed at all by the Reverend Mother, and repeatedly questions her statements and talks back to her. Plus, he keeps his hand in a box that makes it feel like it's on fire, for even longer than the test is usually done.
"The Reverend Mother Gaius Helen Mohiam, Bene Gesserit Proctor who tested Paul's humanity when he was fifteen, deposes THAT HE SURMOUNTED MORE AGONY IN THE TEST THAN ANY OTHER HUMAN OF RECORD. YET SHE FAILED TO MAKE SPECIAL NOTE OF THIS."
Although that's probably a CMOA for Paul Atreides, it's a Dethroning Moment of Suck for the Rev. Mom (though in fairness the above quote is from a list of several things the Bene Gesserit should have noticed, ending with the conclusion that there is reason to suspect some unseen influencing force on the matter).
We only learn of this long after the deed's been done, but when Duncan Idaho was forcing the Sardaukar away from Paul long enough to get away from the office, he apparently killed nineteen of them. At that time, the Sardaukar were powerful enough that a single one of them could slaughter ten house regulars, and even a Bene Gesserit adept. They were impressed enough to hold onto his body and contact the Tleliax to get them to make a ghola.
Of course Duncan's a badass, he's the Swordmaster for House Atreides, one of the more highly-rated noble houses in the Empire. His being the target of cloning fodder also means he is effectively immune to the more long-lasting effects of death, though it also gives him an Iron Woobie status verging on Cosmic Plaything.
Meta example: The book was an inspiration for the song"Desert Rose" by Sting and Cheb Mami.
Paul Muad'Dib Atreides, who is Usul among us: Stilgar, do we have wormsign?
Stilgar: Usul, we have wormsign the likes of which even God has never seen!
Leto II cutting a man's throat with his hand, and then throwing a live laser-shield bomb like a discus so far that it explodes harmlessly in the distance.
Some of Children of Dune's soundtrack was so awesome it's been used in a number of trailers, advertising, and scenes in other works since its release.
Farad'n shows hints of noble bastardry when he throws a spike in the wheel of his mother's plot to eliminate the Atreides rulership by revealing her assassination attempt on Leto II and Ghanima, and freely surrendering her to the Regent. After years of never living up to her twisted standards, this sudden ambush leads her to proclaim, "You're more of a man than I ever thought possible."