I can’t claim to have re-read the whole Harry Potter series before reading the final volume, Harry Potter and the Deathly Hallows, but I enjoyed the final book anyway.
One thing that I’ve appreciated in Rowling’s work is the premise that Harry’s specialness is primarily due to contingent external factors, and these are combined with intrinsic traits that could be part of anyone’s personality. Essentially, Rowling dispensed with almost all the usual mythological framework of inherited position, the sort of thing that was painfully essential to C.S. Lewis’s Narnia stories. It is part of what makes Harry accessible to all sorts of readers: it is non-exclusionary in a way that much of the fantasy literature cannot claim. In this regard, Rowling’s description in Harry Potter and the Order of the Phoenix of the choice by Voldemort in pursuing Harry rather than Neville Longbottom is a repudiation of the usual way in which prophecies get handled in fantasy.
So if you are one of the few people left who read the rest but haven’t yet picked up a copy of the new book, I think that you are going to like it. I think that the scriptwriters will have an excellent base for the movie adaptation, too, so I’m now looking forward to the final movie in the series, which I think is slated to open sometime in 2010.