Even though I do it with a heavy heart, I have to mention a couple of the Harry Potter movies. The first three movies were terrific and didn't leave out anything too important, but The Goblet of Fire, The Order of the Phoenix and The Half Blood Prince were all butchered. I just can't fathom why they would leave out so much stuff from those movies.

They somehow managed to turn the longest book (OoTP), into the shortest movie. And they left out the best chapter in Half Blood Prince, which was The House of Gaunt. That chapter was essential to the history of the Horcrux. Generally speaking, they butchered the memory parts completely.

Although, I was generally satisfied with the last two installments, except for the fact that they almost completely left out Dumbledore's story, not to mention the two most exciting duels in the book... Minerva vs. Snape, was nothing more than a couple of flashy CGI effects, and the duel between Molly and Bellatrix was equally as disappointing. Come on! Both duels lasted no more than thirty seconds each.