> However, the US does not recognize any other country's preferred retirement saving.
This is not completely true: Canadian RRSPs are recognized by the IRS at the federal level due to a tax treaty, though may not be recognized by all states. (For example, I had to figure the interest on the investments for my California return, until I decided to sell the RRSPs to simplify my life.) Other countries may get special treatment for their tax-deferred retirement accounts via a tax treaty too, though it can be tricky to ascertain -- you may end up actually having to read the treaty!
This is not completely true: Canadian RRSPs are recognized by the IRS at the federal level due to a tax treaty, though may not be recognized by all states. (For example, I had to figure the interest on the investments for my California return, until I decided to sell the RRSPs to simplify my life.) Other countries may get special treatment for their tax-deferred retirement accounts via a tax treaty too, though it can be tricky to ascertain -- you may end up actually having to read the treaty!