To stave off recession, the Federal Reserve has been trying to foster more market demand by lowering the federal funds rate. That's the overnight borrowing rate for banks; it triggers the lowering of most other lending rates. This hurts your retirement investments in 2 ways: you earn less interest at the bank and your trip to Europe costs you more.
Lower borrowing rates produce more demand for products and services. But too much borrowing can produce artificially created demand leading to inflation - the lowering of a dollar's value. Don't let a falling dollar bring you and your retirement investments down.
Europe has kept their rates relatively stable for the Euro. As a result the number of dollars needed to buy a euro has been increasing. In a year from March of 2007 to March of 2008, it's gone from 1.33 $/euro to 1.55$/euro . That's a decrease of 15% in the value of a dollar relative to the euro.
You can take advantage of a weakening dollar by have some retirement investments in foreign securities. That's because foreign securities are denominated in - and therefore bought and redeemed - in that foreign currency.
So if you bought a foreign security dominated in Euros with your dollars in March 2007 and sold it in March of 2008, you'd have made 15% on your dollar investment even if that foreign security paid no interest, no dividends, and didn't increase in its value in Euros. Of course, an increase in any of these would add to you're overall gain in dollars and further help your foreign retirement investments.
There are several different ways to place some retirement investments outside the dollar. You can gain instant diversification out of the dollar simply by buying foreign stocks, bonds, mutual funds, ETFs, etc. Just by buying these foreign securities, you gain exposure to currencies that are increasing against a weakening dollar.
If you purchased a euro CD with your retirement plan and the euro rose 3% versus the dollar, then you'd gain that 3% on your initial investment. Plus, you'd get the average interest rate that the Euro CD paid.
Remember, though, that a rise in the dollar rises against your foreign currency, will subtract that percent of rise from whatever gain your foreign investment produce in its own currency. So you could possibly lose some of your initial investment. Therefore, only a portion of your retirement investments should be in non-dollar assets.