This book is a good few years old, but if you're interested in the problems with our existing currency systems, then it is well worth a read:
http://www.lietaer.com/writings/book...ture-of-money/
I think BitCoin is a fascinating concept that I will be watching closely. The speculative and rapidly changing value at the moment is a bit of a problem. I'd like to see a more equitable currency where somehow every individual is allocated the same starting amount. The speculative nature and growth at the moment doesn't make for a very equitable system or a fairer world.. but I still couldn't resist buying a couple myself.
Phil