For this list, I will be ranking all 7 Harry Potter books based off of my own personal opinion. I also would strongly recommend to view my Harry Potter Movie list as well. And I will not bias in this list. Just because Chamber of Secrets is my favorite Harry Potter movie, doesn't mean it's my favorite Harry Potter book (which it isn't). Remember that this is my opinion and probably not yours. So please respect that. Enjoy!
http://www.ranker.com/list/top-7-harry-potter-books/fanboy,
Harry Potter and the Deathly Hallows
Harry Potter and the Chamber of Secrets
Harry Potter and the Goblet of Fire
Harry Potter and the Half-Blood Prince
Harry Potter and the Order of the Phoenix
Harry Potter and the Prisoner of Azkaban
Harry Potter and the Philosopher's Stone