Nemo_: sorry for the relatively poor level of discourse in this thread. Few people without a working knowledge of basic cryptography seem to understand that Bitcoin is, in a mathematical (i.e., true) sense, as indestructible as the hashing and signing algorithms it relies on to maintain integrity. Exchange markets like MtGox and online wallet-storage services like InstaWallet might be hacked and fail, but not Bitcoin (at least not without major mathematical advances that would render the entire Web insecure as a byproduct).

PS. You will enjoy reading this post on the origins of money, in which among other things the author analyzes the common properties of many commodities used as money throughout history -- including not just gold and silver but less-well-known materials like wampun shells, ivory beads, and ostrich egg shells: http://szabo.best.vwh.net/shell.html