I cam late to the party but I've just finished the 7 Harry Potter novels so
a few thoughts in terms of the comparison to the movies so far.
Pretty much an excellent example of a film from a book, a few minor
differences but on the whole it had the feel and compactness you
Chamber of Secrets
Again a movie that kept pretty tight to the novel it was based on.
Prisoner of Azkaban
The first of the larger novels which required significant editing
to produce a viable screenplay but that said it still helf true but
I enjoyed the book more.
Goblet of Fire
My favourite of the movies made so far bascially because it's
the first time we see the trio as young people not as kids and we
get limited Quidditch action. That said I did enjoy the more
complex novel and the background goings on in the school.
Order of the Phoenix
Not keen on the movie and I'm afraid that coloured my reading of
the book. I skipped pages and actually the Quidditch storylines
were pretty entertaining as they played more of a part in the
draconian clampdown on school activites.
I also preferred the expansion on the House Elfs role in the world.
I didn't come away from the movie with a positive experience.
The book is much better and underlines the sometimes hard decisions
a writer and director have to make to try to keep the spirit of the story
while making it work on a screen.
A excellent finale to the series and I'm pretty sure the decision to split
the book in to two movies will prove a good idea and not just for Boxoffice.