Well, this is a big one. I kind of cheated on this one, with the inclusion of series as single items, but I hope you'll forgive me. These books are not the best I read this decade, they're the best that were published from 2000 to 2009. And they're in no particular order.
Harry Potter (Entire Series), by J. K. Rowling: The books that got an entire generation reading. And with good reason, too. They're phenomenal. Harry Potter's journey will be classics from now on, to be passed down from parent to child.
Abarat (Parts 1 and 2), by Clive Barker: This is perhaps the least known one, seeing as the most recent volume was published in 2004. But this insane romp through a world where there are 25 Hours in a day (capitalization intended) and there's a new surprise around every corner is a delight. And these are only the first two of five. Look next year for book three-- Absolute Midnight.
The Name of the Wind, by Patrick Rothfuss: One of the best fantasy debuts in recent memory. It balances nicely the departure from genre cliches and the embracing of them in order to turn them into something different. A must-read, and I can't wait for book two-- The Wise Man's Fear.
The Circle Series (Black, Red, White, Green), by Ted Dekker: A genrebending delight for all fans of fantasy, sci-fi, thrillers and a tale well told. The series that started the whole Books of History Chronicles. Give it a whirl. I think you'll dive deep into its pages soon enough,
Duma Key, by Stephen King: This novel has one of the best buildups I've ever seen, giving great characters before whopping you upside the head with some major twists.
The Thirteenth Tale, by Diane Setterfield: The most "literary" book on this list. Setterfield returns to the style of Jane Eyre, and this Gothic "ghost story" will keep you spellbound. Perfect for anyone who loves books. Even if it doan't seen like your cup of tea, try it.
PENDRAGON (Entire Series), by D. J. MacHale: A fun, epic, 10 volume masterpiece. Bobby Pendragon's journey through time and space has been considered to be as good as Harry Potter, and I'd say it's close.
Mistborn Trilogy, by Brandon Sanderson: This is how trilogies should be done. The first book accomplshes what it usually takes three books to do, and it only builds from there, challenging your perceptions while thrilling you. Wonderful.
Under the Dome, by Stephen King: A 1000 page book anyone will read. Gripping from the very start. One of King's best.
Percy Jackson and the Olympians (Whole Series), by Rick Riordan: Absolute fun. A magical mix of Greek mythology and 21st century life. There's a movie coming out in February of the first book; read it before watching. This series has come the closst to Harry Potter in terms of getting kids to read. Truly enjoyable.
Those were the best of the 00's. What wonders will the new decade hold?