Harry Potter and the Half-Blood Prince

Honestly, I think Harry Potter and the Half-Blood Prince (books 5-7 have always been top tier for me) may be my favorite of the Harry Potter series. I just love the background into Voldemort and we finally start seeing things coming together.

The underlying romance between Ron and Hermione, the romance between Harry and Ginny, Tom Riddle's obsession with vanquishing death and his belief that magic means that one should be master of death, Dumbledore's overall message of more love in this world (ironic that Rowling could write such a character and then have the beliefs that she does... I get in her mind that it isn't about loving someone else, but I struggle to see it in any other way), Dumbledore's speech about tyrants being afraid of someone rising up and being afraid of those that they oppress.

This book has such great moments in it. Finally, the series is no longer light and fluffy always, but recognizes that there are evils in this world and things worth fighting for.