And there's another electronic currency system coming online now that should handle instant transactions well: ripple.com Its a new incarnation of a relatively old idea, but the good thing about the new ripple is that transactions are (and should continue to be) nearly instant. And it is very, very easy to trade bitcoin for ripple using the ripple system, and should get even easier. So I imagine a future where value is stored in btc, and spent using ripple (in any of the supported currencies).