Gold is just a very pretty metal. Lots of things have been used as currency. The gold standard of a currency is that you pay your taxes with it. The Chinese used special sea shells. Most european states prior to the time of Columbus used Silver. The names of the currencies prior to Napolean were based on one roman pound of silver. (Pound Sterling, anyone?) The French called is the livres, the Italians, the Lire. Of course, governments cheat. By the time of Napoleon, the British pound represented about 5 oz of silver.
Among other things used as currency have been Pepper (throughout Europe prior to 1400) Gourds (Haiti still refers to its currency by that name) Salt during the roman republic (Hence the term Salary) copper (During the early roman empire and up until Mejii era Japan) and iron bars (The Spartans didn't approve of commerce)
Gold has advantages as a currency. Its supply is stable. This was a good thing up until the 19th century, when economies began growing at rapid rates. If your money supply stays constant and your economy grows 6% (As was common prior to the Depression) then prices sink at a rate of 6%. If you are a producer, this is painful. If you are a producer and you owe money, this can be catastrophic. (Hence the Granger movements here in the US)
Anything can be used as money. If the supply changes a lot, prices change a lot. Governments always like to inflate, because they always owe money.
Right now, we have tons of money supply that the Chinese are sitting on. They get upset, scared or angry, we are in for some serious inflation.
Gold wont' change that fact. In the modern world, debt is money. It is easy to trade electronically, (gold is really very heavy for low value) and gold is more valuable now as an industrial product than as a reserve of value. The price just swings way to much. It has doubled in price recently. Do you want a standard of value that is that volatile?
If the US government reneges on its debts, gold will belong to the guys with the guns. If they want it. The would be more interested in food than shiny rocks though.