I don't see a fall in the US dollar for some time. As the printing of fiat currency continues, inflation, and bad inflation are sure to follow eventually. For the shorter term remember that all world countries that buy oil have to be paid for in US dollars. The recent quake in Japan was cleverly insured by the Japanese ; they recognized that if Tokyo was devestated the loss would be unbearable so the bulk of their insurance is held by overseas insurance companies, notably USA & Germany. Japan will sell yen to pay for US dollars (yen up 8% this last week) They would like to have the yen devalued to help their exports, and this will eventually happen.
The problem in Europe continues, and Germany is bearing the brunt of Greece, Spain, Portugal, Ireland etc. No one knows who may pull out, default, riot next etc. but right now US dollars are a relative safe haven. even though the US debt is about the same as Spain; for Europe it is the best of all evils. Gold and oil will increase, the latter probably $130 by Christmas and certainly will be higher this summer as the refineries change to summer fuel. Gold would be a lot higher now if it wasn't for the massive control by the illegal games J.P. Morgan and the big boys are playing; gold rises in the US then is quickly sold of at precisely (e.g.) 12 noon in London.
So keep your golden SLI for eight years or so.