Great book. Unfortunately, I've read it so many times that I have become bored of it! My disappointment in the movie version of the book probably has tarnished my enjoyment of the book. I can't get the silly characters that I saw on the screen out of my head. And the jokes that once seemed funny, underground, and eccentric, now seem hackneyed and even worse...unfunny. 
 It is clear to me that Adams wrote this book and the rest of the series on the fly and took very little care to craft the book. Sure, the ideas are zany and brilliant, but they are often unpolished and unorganized...and after many years of reflection and enjoyment...not fulfilling. These books are really what you make of them: I am reminded of a story that I heard Adams tell in person at my university that someone always asks him what the significance of 42 is in the book, and he would always say, my g-d, its a joke! And someone in the audience goes, well, 6x8 in hexadecimal is in fact 42, and Adams just groaned. 
 Still a great book, but unfortunately, I don't think it will stand the test of time, and will ultimately not become a true classic 50 years from now.