The Underland Chronicles by Suzanne Collins
The Underland Chronicles are about a boy, Gregor, who falls underground in NYC and finds a world inhabited by giant bats, rats, mice, cockroaches, ants, and strange people. He (and the readers) also find a stunning adventure. I strongly recommend this series. It includes:
Gregor the Overlander
Gregor and the Prophecy of Bane
Gregor and the Curse of the Warmbloods
Gregor and the Marks of Secret
Gregor and the Code of Claw
Suzanne Collins also just came out with a new book, The Hunger Games, and it looks really good. If anyone who has read it could give me review, id really appreciate it.
Artemis Fowl series by Eoin Colfer
You probably wouldn't expect the Artemis Fowl series to be about a 12 year old genius criminal mastermind. Then again, if you're reading this, you haven't met Artemis Fowl. The only son of a extremely wealthy couple in Dublin, Artemis Fowl has no friends, and wants none. When one of his money-making schemes lands him a fairy, he gets a lot more than he bargained for. I love the way this series takes the way you think about all sorts if things, and makes it all new again. It includes:
Artemis Fowl
Artemis Fowl: The Arctic Incident
Artemis Fowl: The Eternity Code
Artemis Fowl: The Opal Deception
Artemis Fowl: The Lost Colony
Artemis Fowl: The Time Paradox