I was at University when 'The Hitch-Hikers' Guide to the Galaxy' first came on the radio. I didn't have a set, but it quickly became popular among some of the people I knew. The same people who played Dungeons & Dragons and read Tom Sharpe. Unfortunately, as a group, they got on my nerves for a variety of reasons, so I veered away from them and their preferences.

In later years, with a group of more congenial lunatics, I rediscovered Adams and D&D. Oddly, it was a review in White Dwarf magazine (which in its' earlier years covered a wider range of interests) that brought me to Pratchett. It was some years later that I came across Tom Sharpe again - I'd completely forgotten about him!

As to mysteries, I was practically raised on Conan Doyle, but like you, I find Christie pedestrian.