When I first heard of BitCoin, a decentralized (i.e. not controlled by a government or corporation) digital currency, I immediately thought of Neal Stephenson. Why? Well, I have a total mancrush on Neal Stephenson, so he is never far from my thoughts. But a central theme of several of his novels (and a peripheral theme in others) is currency. For instance, in Cryptonomicon, the protagonists are developing a digital currency which is "anonymous, untraceable, and untaxable", but ultimately there is still some gold sitting in a vault somewhere centralized.
But Stephenson's short story "The Great Simoleon Caper" is even more prescient: