Hitchhiker is often found high-up on various collections of the best books, or greatest novels, or other lofty lists. With that in mind, I was expecting greatness.
It was ok...I guess...
It made me laugh several times, and the descriptions and commentary were quite funny, and it was interesting to see several phrases which have worked their way into common usage, but beyond that, I thought it was pretty boring.
I would say that it is worth reading, but don't expect much, if anything. I think if you are only expecting something that is slightly clever, and mildly witty, and not literary genius, you will probably enjoy this book more than I did. I would also suggest reading it in as few sittings as possible. Not much actually happens in the story, so if you take long breaks between chapters, you may get a bit lost.