The Kindle is great for straight reading from start to finish. Not so great for trying to find a particular reference or flipping through pages to put a question to the book club.
I decided to buy the book itself. I wanted the back matter, and wasn't sure that it would be included in the Kindle version, and even if it is, it won't be as convenient to locate when I want to refer to it.
I love my Kindle, but sometimes ya just gotta have the real thing.