Odelay, with One Foot In The Grave and Mutations close behind. And I mean CLOSE.
And I have read Dianetics cover to cover, along with many other of Mr. Hubbard's opuses. My personal favorite is "Have You Lived Before This Life?", which is a collection of supposedly true - but obviously fictional - reminiscences of past lives that scientologists supposedly were able to tap into during scientology auditing sessions. Each chapter is supposedly the case study of a different scientologist's past lives, kept anonymous for privacy reasons, but all of the stories and plot points are obviously Hubbard-ian. (i.e. "I was a pizza delivery man on the planet Zeeb 4,494 trillion years ago.") If you ever see it on eBay, I highly recommend it.