I've finished the last Harry Potter book. It was good. Not great. Basically, I found the first 350 pages or so to be a bit boring and then it finally got fun. The epilogue was a bit disappointing - it doesn't tell you much about anyone beyond Harry, Ron, and Hermoine. That is actually my main beef with the whole book - too little focus on the secondary characters.
I didn't love the first two Harry Potter books - they were fine but nothing too special. I didn't much love the last two either - they were a bit over long and a tad tedious. However, those three in the middle were fantastic. All in all, it's been a great series of books, one that appears to have engaged many children in reading (always a good thing) and rekindled my interest in reading children's literature as an adult (along with His Dark Materials trilogy by Philip Pullman). Not half bad for something started in a coffee shop just a couple of blocks away from where I once lived!