Harry Potter and the Deathly Hallows is JK Rowling's greatest achievement. We watch Harry mature and reach his fullest potential through the densely packed plot lines and emotional confrontations. What I love most about this book (and some would disagree) is that Rowling is not afraid to examine the true cost of war. While many other authors might have been more selective about the major characters killed in their novels, Rowling allows several beloved characters to die as collateral damage, imparting on us the serious nature of war.
Rather than pander to the children's market, she stays true to her story. Not once do any of these characters act out of character. They stay true to themselves while Rowling stays true to her instincts. This is what I love about her .... and what I love about this book.