I really like this Wired article titled Time to Cash Out: Why Paper Money Hurts the Economy. I am very pro globalization and, order
part of that puzzle, is a unified monetary system. I have previously spoken for a world currency, but this is the real solution I want to implement it.
Right now, I carry no cash and pay everything with Credit Card and my check is Directly Deposited. I have no need for a physical currency at all. If I remember correctly, Sweden (for the last 10 years) and Japan (for the last 5 years) have had micropayments able to be made via Contactless Cell Phone Transactions. This is something is starting to be rolled out here in the US too in the last year or so. This is really going to be the wave of the future. I cannot wait. =)
Personally, I like paying cash. I spend less when I do. You feel it when mr. George leaves your wallet.