"A dollar rally agianst euros and pounds", is this a good or bad thing?

I’m doing a project for school and i was wondering if anybody could help explain this article

http://www.forbes.com/2010/01/04/yen-pound-euro-intelligent-investing-dollar.html

If you belive in Adam Smith free market system, it’s a good thing. The central banks in those countries have no power to influence the exchange rate directly.