I shall have to say the third book, Harry Potter and the Prisioner of Azcaban is the one I've liked the most. It was so funny! Besides we get to learn so many things about Harry's parents and his friends. I mean, three key characters are introduced to the series: Sirius Black, Remus Lupin and Peter Pettigrew.
Sirius Black: I sort of have love-hate relationship with him. He is my favourite character's worst enemy (Severus Snape) and I really think that he is a complete idiot for going to save Harry at the end of the fifth book (which by the way it's the worst one yet). Yes , heis his godson and the lot but didn't he realise what he MEANT to the boy? Because here there is an orphan whose only family treated him like crap and who comes to this school who everybody worshipped him and had the higgest expectations of him and that even though he loved the wizarding world we have to admit: those guys only cared for Harry when he was the saviour and when the paper said the wasn't mad. But then comes this man who stayed 12 years in Azcaban and when he finally got his freedom he goes to the place where he had more chances of getting caught that anywhere else (except maybe the Ministry of Magic, but just maybe) just to protect a kid who he hasn't seen in years. No one had done that for him. Not because he was rich and famous and because he was the boy-who-lived-so-he-has-to-be-protected-a
t-all-times. And then, apart from all that he protects them facing him by himself a werewolf. Griffindor indeed. So my conclusion? He was the best motivation for Harry to fight in the war.
Now, Remus Lupin. Aw, there's a character you just have to love. He is great! Really humble and probably the best DADA teacher ever, he is rather complex but in a good way. I could picture him in a super granny-who-bakes-cookies-but-also-kicks-b
ag-theives-behinds. well... maybe not baking cookies but something along the lines.
And Peter Pettigrew, the one everybody can easily hate. He makes a good pathetic minion, although he does have a rather important role later on. I loved it when Snape kept ordering him around in book 6, it was hilarious.
So, there there is, my writer's block dilema and answer... fell free to coment or debate!