The Relisten continues!
Prisoner of Azkaban is always one of my favorite Potter books. The introduction of Remus and Sirius, Hagrid's disastrous classes, Hermione's schedule, winning the Quidditch Cup, these are some of my favorite things. There is also the feeling you get on a reread that this book is really the last one about Harry and the gang as children. I got pretty teary eyed in parts as I was remember what is going to happen in books 5 and 7.
I really love Goblet of Fire! It's the first big book and so many things happen, for the story and as setup for later parts, that you just rocket from event to event. All the relationship stuff, the Harry-growing-up stuff, and of course Cedric, and the interactions with Sirius (which got me teary again). It's all so good.