There would be a sharp sell-off of the US dollar as investors abandon the currency in favor of a more stable destination. Ordinarily, the euro would be considered a likely candidate. But the eurozone countries are presently mired in their own debt crisis. This helps explain the record price of gold breaking through the $1,600 barrier.
Whether this money finds its way to gold or Canadian dollars or Swiss francs is irrelevant. In the wake of a default, the US dollar would fall against most of the major currencies. Consumers in the United States would pay significantly for almost all their imports – from toys to gasoline.