The Official Ubuntu Book by Benjamin Mako Hill and Jono Bacon, Corey Burger, Jonathan Jesse, Ivan Krstic.
I have been working with Ubuntu 6.06 for the last couple of months since its release and have been impressed with its simplicity and elegant design. I think it's a good distribution for anyone starting out with Linux. Likewise, The Official Ubuntu Book is an excellent starter book for new users. It includes a live DVD Ubuntu disk that let's you do a "try before you buy" test of the system before you install it.
The book is well written and includes interesting chapters on the history of Linux and the Ubuntu project. There is good coverage of the installation process for both the desktop and alternate CD versions. The chapter on using the GNOME desktop and its application programs is clear and useful. There is a very helpful chapter containing tips and troubleshooting info along with plenty of links to where to find help from other members of the Ubuntu community. There is also discussion of the server and Kubuntu (KDE centric) variants. For the new Linux user this is great place to start.
Disclaimer: I received a review copy of this book from the publisher.