Combined with a Moment Of Heartwarming: When Anderson is told that The Alliance intends to hand Adam Jensen over to the Order Church, his response is absolutely awesome.
Anderson: When you hand over that evidence to the Council, and when they come back to you and declare Saren rogue, vindicating you in front of every representative of the Citadel races, I want you to remember this: It was a quarian, a turian and a cyborg that made it all possible.
Let's bask in the moment that was Adam taking down all of the Asari Huntresses. Are you basking in it? Good, keep basking in it.
The Normandy team try to figure out how to take down Adam non-lethally in the event that they have to. To sum it up? They can't think of one that would work.
The fight between Adam, Sarah, Garrus and Shepard's killer. It gets the upper hand for a minute, but when Adam's able to hit it... well, let's just say it was quick.
Hein's speech to Tali in Chapter 18.
Hein: I'm going to turn Jensen into the most powerful human being in the Galaxy. I'm going to make the rest of mankind turn green with envy and stew in their jealousy as Jensen comes to their rescue, again and again and again, and go mad when he fails to turn into the monster they all expect him to become.
The end of Chapter 20. Manah T'Soni's spent the past few days starving to death in Caleston's Templar-enforced "Alienage", resisting her mother's scrying attempts(the latest being "Don't expect to be rescued by a storybook hero") by stabbing herself with bits of broken glass when all of a sudden a mind controlled Templar Caim shows up in a fire breathing Wanzer, burning the slum (and all its inhabitants) to the ground to smoke her out. This additional atrocity and the events which led her to be free from her Justicar handlers (her handlers were responsible for the planet-wide riot) leads her to beg for death instead of capture. He is about to grant her wish... aaand then Jensen makes his Big Damn HeroesEntrance via Drop Pod. The Cybernetic Knight Errant simply takes in the scene, pops his Absurdly Sharp Blade, and prepares to make him some Templar sashimi.
Caleston in general, summarized by Hein in Chapter 24.
Hein: No, it wasn't a dream. No, it wasn't VR. Yes, Caleston went to hell. Yes, you went down in that hell. Yes, you faced off against a machine possessed by an extra-dimensional being. And yes... for a few glorious minutes you wielded the power of a Demi-god and killed that monster... and in the process saved more lives than you can even imagine. You're a hero, Adam.
Wrex assaulting a flying gunship with Kasumi on his back in mid-air. Then using his Templar Axe to bite into its armor.
Adam vs. Kai Leng or more notably Adam's use of Break Them by Talking to exploit defensive holes in what should conventionally be more skilled opponents.
Garrus' Big Damn Heroes moment. Dropping out of a flying gunship in midair using his new flying Power Armor, dodging gunfire and explosions, leaping into the middle of an active killzone all to save his friend.
Chapter 41: Aya punches a flying biotic shark to death!
Chapter 41: Garrus dual-wielding anti material rifles and slicing biotic sharks in mid-air combat.
G:Wait a minute. Did I just kill a flying shark by dual-wielding two anti-materiel rifles? Whilst flying at Mach 2 at high altitude?
Yes I did.
Ship with biotics.
The entire fight between Johann, Jensen and Scholar.