The most fun book I've ever read is the Norwegian book "Madonna-gåten" (The Madonna Riddle). It is a spoof of "The da Vinci Code". In order to understand and enjoy the "Madonna-gåten" one must have read "The da Vinci Code" first.
"The da Vinci Code", I found interesting as well.
Authors that interest me are Dean Koontz and Clive Cussler.
When it comes to the "all-time-high", it must be "The Ultimate Hitchhikers Guide" by Douglas Adams.