Who likes books?

A little while ago, I found a service called lulu, and I figured I should probably try to write a book. I've been thinking about it, and I have a level of "expertise" in a couple of areas. I was thinking about one of the following:

• Ubuntu for Windows Users
• Solving The Riddle of GEB:EGB
• Introduction to PHP
• Introduction to JavaScript

They're in the order of likelihood.
I like the idea of Ubuntu for Windows Users, because I know too many people who will not switch to Ubuntu simply because they're too good at Windows. Its like QWERTY/Dvorak, No one will switch because it will take time, even though its way better. Switching to Ubuntu, or any distro of Linux isn't that hard, you just have to take a leap of faith.

Then, I also love Godel, Escher, Bach: An Eternal Golden Braid, I hope it wouldn't be illegal to mention/quote his book, however. But the 777 page book is filled with hidden "riddles" and a some self-reference humor.

The others, I probably won't do. I barely have any "expertise", but I could do the real PHP/JS for complete morons.

Please tell me what you want me to write, either one of the above or something completely different, in the comments section.