Canadian manufacturers and those who need to buy imported capital goods to stay competitive can more affordably do so now (and better get going soon). Some economists have long warned that the Canadian economy was getting too hooked on a cheap dollar and deferring improving efficiency.
BTW, I was reading in Forbes.com, FT.com or some such about the U.S. government andhow it shouldn't be so happy with a weak USD. The U.S. government pressured the West German Government to revalue the Mark throughout the '50s and '60s. When Bonn did so in the '70s, all it did was unleash inflation in the U.S., and even worsened the trade deficit, with Germany. Don't know how much that was in combination with O.P.E.C. and Vietnam war costs though (sounds familiar except this time it's China and Iraq?) If the Yuan revalues, it'll make capital equipment even cheaper for Chinese manufacturers and give a helping hand for a huge and rapidly-industrialising economy.
In a word, the U.S. should be careful of what it wishes for lest it gets it.