[maxtower]

I looked over the Liberty Dollar site, and it seemed kind of scammy to me. Fine if you want a Ron Paul coin for your collection, but otherwise completely impractical.
1. You can't spend them anywhere. I wouldn't do as they suggested and pass it off as real currency.
2. Buying bullion off ebay is a much cheaper way of obtaining the underlying metal.
3. If the value of the coin did diverge from the dollar amount, you are supposed to pay taxes on the gain once you sold it.

Practical alternative currencies could easily exist if taxes were eliminated on gold gains. You could get an account at goldmoney.com or e-gold, and then get a debit card which links to that account. Whenever you get paid just deposit the money into your gold backed account. Then buy everything you need with your debit card which would do the conversion automatically when you go to spend the money in whatever country you are in. Its not really practical to do this now, because you'll end up paying taxes on the gains whenever you go to spend the money.