Ever since before even the formation of the European Union, there has been a sizable contingent of economists who were skeptical of the idea's merit, and the recent issues with deflation for the euro seem to bear some of those issues out. In this kind of environment, the U.S. dollar is a much better investment option.
I don't know anything about euros, but I like US Dollars. I am a Canadian citizen and do some work where I am paid in US Dollars and the exchange for me works out in my favor. So if the euro is declinging, it makes sense to change to US Dollars.
Look at the long term trends and the history of the euro and the U.S. dollar and you see ebbs and flows to both, yet they both see overall gains. Divesting from euros is not a recommended choice when the trends suggest the euro will experience a growth again as the currency goes through its cycle.
The last decade has been a scary once for investors of all levels. Currencies like the euro and the U.S. Dollar have seen alarming falls in their value and a slow climb back up to previous values. Repeatedly we've seen that these seemingly separate currencies are in fact intertwined and directly affect one another in our current global economy. When taking into account the recent American Recession and the U.S. Dollar's slow climb in value over recent years I would not recommend switching between currencies to any investors.