As I'm getting older I'm starting to realise there are some texts out there that are still very relevant, even if they are years old. Would the original K&R book be of value to me as a C programmer after 15 years? Definately.
The Camel Book is a great read; I thoroughly recommend it and have found myself turning to it time and time again in the last 5-6 years. There are some interesting chapters to browse through from time to time, such as optimised methods of coding for speed, terseness, maintainability, etc.