The only parts they absolutely should not have left out are Harry finding out that it was Snape who overheard the prophecy, and they should have included more of an explanation of why Snape was the Half Blood Prince. I would consider those integral to the story. I would have loved seeing the battle as the Death Eaters left Hogwarts, but i suppose that was not really integral to the storyline. Other than that, the humor was fantastic, and I thought the cave scene was especially well done.