Ok, I just finished Harry Potter and the Half-Blood Prince. As you may have guessed from the title of this entry, this is the best Harry Potter book yet. It's gripping, moving, and full of surprises.
Once you start reading this book, you'll have a heck of a time putting it down. That is a good thing, because you won't find out who the half-blood prince is, or what major character dies, until the final chapters of the book (and I'm not going to give away spoilers and say who they are, so don't ask). Besides that there's betrayal, romance, mystery, and adventure aplenty. The book is chock-full of interesting scenes and characters. The death scene itself was very moving, so much so that I was actually crying afterwards.
The death gives Harry another reason to go after Voldemort (and a certain other old enemy). The book also reveals what may be Voldemort's one weakness, which Harry will have to exploit to defeat his arch-foe. We are also told what Harry's plans are for the next book (and boy do they sound interesting). I can hardly wait for him to catch up with Voldemort and [name deleted to prevent spoilage].
If you're a fan of Harry Potter, you must buy this book. If you're not, then read this book and you will be. I give it 5 yo-yos.