Hans Brasch's pre-mortem one-liner — "This is for my wife Anna, whose name you never asked, you NAZI SON OF A BITCH!!!"
A Hymn Before Battle
Mike's first experience with real command is a Moment of Awesome from start to finish, but he caps it off by being the first human ever to take down a C-Dec battleship, and he does it by jumping onto it with an antimatter frigging bomb.
Furthermore, the non-ACS survivors of the Battle of the Monument become known as "the 600", which, in turn, form the core of an ACS support force called "The Ten Thousand", which take on the Posleen in the similar numbers as the ACS, only without using Armored Combat Suits.
At one point the human survivors of the retreat up the East Coast have stopped retreating in Washington DC. In Chapter 64, as they are preparing to fight back at various points, an officer directs his men to dig trenches and fox-holes in Arlington Cemetery, commenting "The soldiers, sailors and Marines buried on this hill would have no argument with a little jostling. They understood". If anyone would understand why their graves needed to be disturbed, those in military cemeteries like Arlington would, in fact, understand.
All throughout the series, the Posleen encounter massive explosions and traps, marked by the Army Engineers (Sappers). In Chapter 65, the Posleen encounter the same symbol in Washington DC. When they recognize it as the headquarters of the Engineers, they literally turn around and run (which Posleen never do). The reaction of the Engineers who had in fact trapped their headquarters to take out the entire Posleen force was hysterical laughter, which is said to be easily restarted by using a hand to simulate a Posleen crest rising up off their head in fear while putting on an Oh, Crap! expression.
The entire first eight paragraphs of Chapter 71. It details a series of vignettes as to how and why the humans would stop running and make their stand, and ends with "Sure, most [humans] had run. But more had stayed. And the [Posleen] would have the [Washington] Monument over their dead bodies".