Many economists in the region argue for a more flexible currency system, starting with a Kuwait-style currency basket, so interest rates can reflect the realities of a region with a very different economy from America's.

ECONOMIST: Monetary union in the Gulf

The question of how much time has been bought for China depends on how flexible the currency will become.

FORBES: China's Currency Fortune Cookie: What's Inside?

Not enough Swedes are convinced that the path to prosperity is strewn with lower taxes, a more flexible labour market and entry into Europe's single currency.

ECONOMIST: Sweden

If the single currency forces governments to make their economies more flexible, as many of its proponents hope, it will bring extra benefits, not impose greater costs.

ECONOMIST: Europe's mid-life crisis

Any country that abolishes its own currency needs to have an economy that is strong and flexible enough to accommodate external shocks, since it cannot ride them out by printing money.

ECONOMIST: Ecuador on the brink