The conversation between Harry and the spirit of his father.
Malcolm Dresden: Yes. I'm dead. But that doesn't mean that I'm not here. It doesn't mean that I don't love you, boy.
This great line, from a later conversation:
Malcolm Dresden: Son. Everyone dies alone. That's what it is. It's a door. It's one person wide. When you go through it, you do it alone. But it doesn't mean you've got to be alone before you go through the door. And believe me, you aren't alone on the other side.
When Harry is trying to convince an EMT to talk to him, the man is initially worried that Harry will think he's crazy for reporting it, and doesn't trust him...at least until he remembers where he'd seen Harry before, when he and Michael had been arrested for breaking into the maternity ward a few years back. He says the hospital they're in, Cook County, was suffering the highest rate of Sudden Infant Death Syndrome in the country, up until that night. Ever since then, they haven't lost a single baby - and he realizes that it was Harry and Michael who "did something" to stop it. It's a small but powerful scene that shows how what Harry has been doing has really been helping people and that his struggles aren't going unrecognized.
Butters helping Harry rehabilitate his badly burned hand note Harry burned it severely in a previous adventure, and has spent most of Dead Beat too traumatized to use his fire spells. by buying him a guitar and a copy of Guitar for Total Idiots. Harry settles back to read it, and casually lights some candles using magic.
I stopped and blinked-first at the candles and then at my burned hand.
"What?" Butters asked.
"Nothing," I said, and opened the book to look over it. "You know, Butters, for a mortician you're a pretty good healer."
"You think so?"
I glanced at the warm, steady flame of the candles and smiled. "Yeah."
At the end of the book Morgan finally acknowledges that Harry isn't actually malicious, though he still considers him of sufficiently poor judgment to be dangerous. There's still some enmity there, but it was a big concession that must have cost him a lot to make.
There's a similar one on Harry's side where he realises Morgan isn't being personal, he's just a burnt out cop projecting all of his trauma and doing his utmost to stop it happening again. He still dislikes him but feels some pity as well.
Finally, there's a moment of fridge heartwarming when you find out Morgan was taking over from Butters on the drum in the latter part of the battle. While circumstances required it note Butters needed to heal Luccio, and the T-rex would go out of control if it stopped. it's still pretty impressive that Morgan supported Dresden in battle, by holding together a necromantic spell he had severe reservations about no less.