The yen has appreciated partly from speculator activity, and partly from massive repatriation of funds from abroad, as Japanese firms bring home cash to pay out on insurance claims, and of course devestated families bring home the "rainy day" money to pay their way through their own wrecked lives.
Most Americans are not in the export business. Therefore it has to be said that a weak dollar does not bring much direct cheer to any other large chunks of the population.
On the other hand most Americans DO fill up their fuel tanks, consume foreign goods, and of course eat.
It is primarily a weak dollar that keeps the commodity bubble going, and the cost of living so high.
I dunno about you, but I'd rather have my cost of living expenses down by over 50% in exchange for having to sell my wares to the local population rather than abroad.
There again, I'm NOT in the export business. I DO fill my tank, eat imported food, and buy imported electonic goods. I'd like a strong pound upto the point where it does not increase unemployment. Trichet, across the Channel from me, thinks like one of our previous Chancellors that "Unemployment is a price worth paying". If you don't have a job, you don't have any of this more valuable currency, so he's obviously 7 cans short of a six-pack!