Regarding some of the posts here
Whether you buy the currency argument or not, it does not matter because it is already true. Currency traders all over the world are taking bets already. It has been old news that the dollar is overvalued even before the Euro. In fact, the dollar's position as the only realy global and oil currency is one of the reasons the Euro was even implemented. And in case you do not watch the news, this issue has pretty much been let out in the open and confirmed by recent events.
Now I personally think that Western and Central Europe is a dead economy. It is old, yet stable. However there is no growth or opportunity left there.
Eastern Europe is another story. Being that the Eastern Europe block is about to become part of EU, means that the Euro can get some momentum. Also, with the addition of these new countries, the European Union's GNP and GDP becomes comparable if not greater than USA.
Since the dollar has been the oil currency for decades, the general idea is that the Fed could always print more dollars and there will always be international takers. There would be a slight inflation effect but nowhere to the point if the dollar was not the reserve currency. The basic idea is that dollars are always needed since oil is always needed. Those same dollars find their way back to the US as foreign investment hence growing our economy. This is also how USA (and no other country) could sustain such trade deficits years over years.
Now if this were to change and the Euro would become the new oil reserve currency, USA dollar denominated assets would basically get dumped. All dollar reserves would be pretty much converted to euro, hence dumping the dollar. What you would basically see is a standard third world bubble burst scenario. Except that unlike Argentina, US holds real value to the world economy. Still, a devaluation would occur.
OPEC is already considering switching currencies. Iran and Syria have pretty much done so. Venezuela is not even using a currency, but trading commodities. The main reason for this is the state of US economy and the recent bubble. Let's be honest, this country is in serious debt and that situation is not changing. Almost all of consumer spending over the last decade was based on pure credit. Same goes for the corporates, who still do not have the brains to completely stop their borrowing. There is also technology spending which is out of wack thanks to Microsoft.
But with Iraq, this can all be changed. Iraq is not part of OPEC and can easily produce oil for US$10 a barrel. This would disband OPEC (old goal of US and the world), and preserve dollar stability at least up to a point. Also, with Iraq, US can convert the rest of the Middle East to be an Americanized democracy (another old goal of US) and use the dollar as well.