The U.S. dollar looked weak for considerable stretches of the last decade, but the global financial crisis gave it a boost. And the current sovereign debt crisis in Europe is likely to ensure that the dollar retains its status as the world's dominant currency, despite some down years.

Over the next year or two, experts see the dollar strengthening against most other currencies except the Chinese yuan and the currencies of some emerging countries, like Brazil's real. In the long term, many experts had predicted that the dollar would again begin to weaken, but given the magnitude of problems currently plaguing its chief competitor, the euro, that's no longer an automatic assumption. Observers worry the conditions that led to the recent EU bailout of Greece could spread to other countries in the euro zone, like Portugal, Spain, Ireland and Italy, further damaging the euro's value.

"One or two years ago, everybody said the dollar was doomed," says Barry Eichengreen, a professor of economics and political science at the University of California, Berkeley. "Now people say the same thing about the euro."