A few years ago, I read Discipline by Paco Alghren. It's a fun read and raised some interesting philosophical points.
From what I know about Paco, he is (and I use labels lightly--always) a free-market libertarian who is supportive of a gold-based economy. He seems like teh type of person who woudl agree with the goals of BitCoin.
Anyway, if you want to see an intriguing fictionalized account of what a world would be like with a private, anonymous currency, you should check the book out. I don't remember what he called the units but they were backed by gold stored with a reputable Swiss bank and could be tied in with a debit card and used anonymously.
When I found out about Bit Coin I immediately recalled that section of the book.
I assure you I'm not a shill for Alghren but I enjoyed the book for that reason among others and I thought others might as well.