My favorite HP book is actually the last one Harry Potter and the Deathly Hallows. I think that Rowling did a fantastic job wrapping up the series and giving readers a sense of closure. While I love all of the books this is the one which I was the most impressed with, because I have to assume this was the most difficult for Rowling to write. The only thing that I did not like was the Epilogue. I thought it was a bit cheesy. Overall I was happy with how the series ended.