After reading the entire series multiple times over the years, I have to say that the seven books as a whole make one big story, and I have a hard time separating them in my mind anymore. As her writing matures and develops with each book, so does Harry and his friends as they grow up, and it feels like a natural progression from starting as an 11 year old boy in our world growing to be a man in the wizarding world who... well, I'm not going to spoil it for anyone who actually hasn't read them or seen all of the movies yet.