One of my all time heroes, Douglas Adams, unfortunately died long before his time should have come. The funniest writer I know, as well as being scientifically interested and interesting, his books are essential reading. On the link above you can find a memorial speech.
My favorite book is his probably far most popular book, The Hitch-hikers guide to the Universe. I even liked the (a bit strange) movie they made from it. I know a lot of people were fond of the older BBC series as well. In addition I have to say they I really liked the book “A salomon of doubt”. I love the way he wrote about God and atheism. According to Richard Dawkins he might even be Richard’s “only convert”.