Also, I love that we get to see Dumbledore's true badassery in this section, as he immediately figures out the Moody situation and deals with it without delay. Harry says Voldemort is back? Ok, then, let's get real about this and see what we can do to stop it. Oh, and Minerva, while we're sorting things out, go get that black dog from my office and tell him we'll be right in. Moody is really Crouch sipping Polyjuice Potion to make him look like Moody? Truth serum, stat. He also wears his scary face and brooks no nonsense. I like that in a wizard.
There is so much set up for Book 5 in the last few chapters of Book 4, it makes me all tingly inside. Not set up like Book 4 loses its way, but Voldemort comes back, we learn who really is a Death Eater (no surprises there, quite), the Weasleys are called upon to be awesome yet again, Snape goes off on some undefined errand for Dumblydorr, the mystery of Crouch is revealed, Sirius shows himself to his fellow Voldermort-haters, and we just know that things are going down. It's like it's impossible to read this scene without hearing dramatic but excited music playing in the background.
I know there are a lot of things that happen that are fascinating that aren't directly related to Voldemort's return to power (Fred & George's money, for one, and the tournament itself, for another), but I am easily distracted by dramatic crescendo-ing conclusions, and now I'm all giddy for the next book.