All five books in one PDF. (Plus many bonuses and "Lost chapters.")
Found the link while lurking for the ebooks.
Code:
http://rs161.rapidshare.com/files/48797008/Douglas_Adams_-_The_Ultimate_Hitchhiker_27s_Guide.pdf
This edition is pretty sweet, considering the author says that he contradicts himself so many times, he explains in the prologue that this is directly reflects 5 of the many Radio scripts.
Enjoy!
Thanks to everybody who uploads nice files.