Oh, my, where to begin!
We had a great theater full of people with us. We laughed, we cried, we cheered!
But...
There were things different from the book and/or stuff that annoyed me:
Ariana's death is never really explained.
Luna was with The Big Three at Shell Cottage before the break in to Gringotts, and then miraculously is at Hogwarts when The Big Three get there. She does not come later through the passage between The Hog's Head and the Room of Requirement.
Harry does not use the Cruciatus Curse on Amycus Carrow. In fact, that entire scene does not happen. Both Carrows make only a
very minor appearance.
Percy never shows up.
Fred does not die on screen. Harry sees the Weasleys surrounding Fred's body, but Fred's actual death scene does not occur.
Neville indicates she has a thing for Luna and that he was going to tell her. We see later that the two of them are together. Jo Rowling indicated at the Carnegie Hall show a few months after the release of the book that Neville married Hannah Abbott.
Hermione and Ron tell Harry they are going to get a Basilisk fang before they run off. They kiss in the Chamber of Secrets. Ron never says anything about warning the House Elves.
Crabbe is replaced by Blaise Zabini in the Fiendfyre scene, I think because the actor who played Crabbe had some drug difficulties at the time. Goyle is the one that casts the Fiendfyre in the movie and dies.
The Centaurs do not fight in the Battle of Hogwarts. They are not seen at all.
Snape is killed in the boathouse, not the Shrieking Shack. His memories are in tears that he sheds as he dies. It was still very moving.
Snape's memories are greatly abbrigded, although it is obvious that Snape loved Lilly.
After Harry's death, Tom's curses continue to affect the grounds and people at Hogwarts. In the book, it mentions that Harry's sacrifice gives everyone at Hogwarts the same protection that Lilly's death gave Harry. Nothing like this is mentioned in the movie.
Harry reveals himself as alive as soon as Neville stands up to Voldemort. The scene is changed dramatically. Nagini is not killed right then, as Neville
does not know at this time that Nagini must die. Neville does have the Sword of Gryfindor, but the Sorting Hat is not set ablaze nor is it placed on Neville's head. As soon as Neville takes a swipe at Tom (not Nagini) with the sword, Harry falls out of Hagrid's arms and runs off, showing himself to be alive.
Harry and Tom DUAL throughout the castle. Harry, Ron, and Hermione all try unsuccessfully to kill Nagini. As they fight, Harry warns Tom that Harry is the true master of the Elder Wand due to is defeat of Draco, but this happens right before a scene where Harry flings himself and Tom from a balcony. The two of them fly around and struggle before crashing to the ground. They continue to dual and their wands lock.
Harry NEVER offers Tom forgiveness nor mentions that Tom should try showing remorse. Only after Neville FINALLY kills Nagini does Tom's wand flip out of him hand, however, Tom's wand does not hit Tom with the killing curse. Instead, Harry catches the wand and Tom crumbles into dust and soot. This occurs outside the castle, and there are no witnesses.
Note that while there were cheers and crying and clapping in other parts, nobody said anything when Tom died. I think everyone was overcome by the shock of
how much it got screwed up!
After Tom's death, Harry breaks the Elder Wand in two and throws it off a bridge. Harry does not use it to repair his own wand, or does he have it buried with Dumbledore.
While visually stunning, and very emotional (up until Snape's memories, at least), the movie lacked a lot that gave the book it's character. It's like the writer and director read the book, but just didn't get it.
this movie.....we waited, we applauded, we laughed, we applauded, we cried, we cried, we cheered, and finally big applause and big crying time when we all realized that it was all over 
wouldn't know what's missing....yep, my youngest DD11 has only read the first 3 books while my eldest DD has read all of them at least 6 times....
