I enjoyed the book. It was probably because of the whole mystery of the identity of the Half-Blood Prince. It's been a couple years since I read it though. Thankfully, we'll be in San Diego next week and I can pick up the rest of the books and bring them back with me.
If people are looking for a book/movie that's good as a stand alone, then this is probably not for them. I think it's a necessary part of the series though. Can't wait to see the movie in 2 weeks. Oh well, I've waited this long, so I imagine 2 more weeks won't kill me. At least I have something to look forward to after Comic-con is over.