Hard not to build hopes when you see what CAN be done when a Director is lovingly faithful to the story (Rings).
Personally I think the Potter movies are OK, enjoyable although far too short to do an adequate job for those of us who love the books (you could seriously make an argument that 2 movies per book are really required).
A Series of Unfortunate Events was one of the worst movies I've seen in a while, so I guess you can put that one down as a 'disappointment'.