Did you like Harry Potter? If so, try the short, complex series for teens featuring magic, royal blood lines, the kind-of-but-not-really undead, and a sassy talking cat by Garth Nix, called the Abhorsen (also known as Old Kingdom) trilogy, started in 1995.
Its first book, Sabriel, features a young girl who must rescue her father from the depths of Death itself. Along the way, she is helped--or perhaps hindered--by her father's "pet" cat, Mogget, and a strange boy she released from an even stranger prison.
The second book, Lirael, introduces a new character, the dark-haired Lirael, who feels absolutely isolated in her home at the Clayr's glacier. In order to gain a friend, she has to create one out of magic she learns as a Second Assistant Librarian. With her new friend, the Dog, she must help Sabriel's son, Prince Sameth, fight to save the world.
In the final book, Abhorsen, Lirael, who is now Abhorsen-in-Waiting, and Prince Sameth face off against the evil threatening the world, with the help of their friends and families. The climactic ending to the trilogy provides interesting insight into society. Publisher's Weekly stated that it is "at once an allegory regarding war and peace and a testament to friendship...a thought-provoking fantasy."
Nix also has a few series for the slightly younger crowd, including the still-in-progress Keys to the Kingdom, vaguely reminiscent of the fantastical world of Alice in Wonderland, and the magical Seventh Tower series, starring the downtrodden and loveable Chosen named Tal.