Crime lord John Marcone, when trussed up and hanging over a pit as bait for said loup-garou, uses a knife his captors didn't find, and instead of cutting all the ropes and freeing himself, cuts one rope so that Harry and Murphy can climb out of the pit and away from the werewolf—though this leaves him in considerable danger. And he banters with Harry while he does it. Oh and does it in the dark.
He's also hanging upside down while he does this. He doesn't just cut the rope, either- he throws the knife, despite all of the mentioned circumstances, and manages to hit the rope accurately and hard enough for it to work. Harry remarks on this achievement of Marcone's in his narratives a few times in later books, because it was damn impressive.
Speaking of Marcone, Harry's conversation with him in his awesome definitely qualifies.
Harry, after donning one of the cursed wolfskin belts of the Hexenwulf and becoming (temporarily) a werewolf himself, realizes that the Black Magic of the artifact is seducing him into doing and becoming something that appalls him, and rips it off and flings it away. Given the overwhelming and addictive appeal of Black Magic in this series, given the fact that it was stated earlier that it was practically impossible for someone who'd tasted the power of such an artifact to turn their back on it, and given that Harry—weak, wounded, unarmed and stripped of magic—was ready to die as a human rather than live as a monster...this was a Crowning Moment of Awesome from every possible angle.
Given what happens in Changes and Cold Days, this could easily become Fridge Horror later in the series.
Harry pitches himself out of a moving vehicle, downs a hella-powerful pick-me-up potion, stands up, and then explodes a pursuing pickup truck's tires, sending it careening off the road.
While humming Carmen as an incantation.
And a while later he disperses a lycanthrope's (read: Berserker's) bloodlust with the magical equivalent of a slap.