USD I think that would be by far one of the worst investments long term
Investors often seek safety from financial market turbulence in US government bonds since they offer virtually no risk of default and, unlike cash or gold, provide a yield. At the same time, sovereign debt default concerns outside the US, e.g., Iceland, Dubai, and Greece, have been linked to short-term rallies in the US dollar and have diverted attention from the fiscal challenges facing the US. However, since seven US states are in worse financial condition than Greece, Ireland, Portugal or Spain, shelter may prove hard to find. With a $3.83 trillion budget, a $12.3 trillion federal government debt, a $1.35 trillion 2010 budget deficit and $63 trillion in unfunded liabilities, the fiscal condition of the US has come into question and foreign interest in US Treasuries has declined. In late March, it was reported that the 10-year US Treasury Note yield had risen 30 basis points and that foreign holders of 10-year Notes were selling in record numbers.
- http://www.kitco.com/ind/Hera/april082010.html