I have probably re-read this book at least ten times by now. It's always one of my favorites and I love how JK Rowling's series grows with the audience as well as seeing how she herself grows an author over the course of Harry's time at Hogwarts. I reread this book and the rest of the series every year starting January 1st. It feels like going home.
The Slytherin special edition of this book has some wonderful additions, including character profiles, house information, and a lovely map of the Hogwarts grounds. The sprayed edges are quite possibly the best thing I've ever seen on a book. I am so happy I got the entire set of special editions, even if I am just Slytherin myself.