Harry Potter 1-like both book and film
Harry Potter 2-like both book and film
Harry Potter 3-like the book, hate the film
Harry Potter 4-like the book, hate the film
Harry potter 5-hate the book, like the film
Harry Potter 6-like the book. (I didn't see the film yet)
Harry Potter 7-book was somewhat a let down. The first part of the movie was good so far. I hope to see part 2 when it comes to theaters.

Most definitely the books.

I love movies 1-3 and 7, and I like 6, but 4 & 5 were just bad. The films cut out too much, and not everything transalates well. Overall, the cast & crew have done a great job, but in other places, they've failed.

Much better, in general.