Ubuntu has experienced its share of success, but it’s still relatively unknown amongst non-technical people. Many aren’t aware that an open source operating system actually exists, and those who are lack the education required to move comfortably from Microsoft Windows to a Linux-based desktop. Ubuntu for Non-Geeks: A Pain-Free, Project-Based, Get-Things-Done Guidebook, by Rickford Grant, introduces non-Linux users to the world of Linux and shows them how to be productive in a complete Linux environment.
Great review by James F. Koopman. Read more on linux.com
a non-geek's blog 
“Ubuntu has experienced its share of success, but it’s still relatively unknown amongst non-technical people.”
I know some hackers and they use Ubuntu, I watched John Maddog’s talk and he uses Ubuntu, Ubuntu is for who want an OS ready and easy to use, there is Ubuntu server too I’m using it here and it’s so stable. The book sounds good! 🙂
I used to run ubuntu server, but now I’m on debian (for server, because I run Archlinux as a desktop OS).