One of my favorite features of The Economist is their Big Mac index. As they (always) succinctly explain:
Burgernomics is based on the theory of purchasing-power parity, the notion that a dollar should buy the same amount in all countries. Thus in the long run, the exchange rate between two countries should move towards the rate that equalises the prices of an identical basket of goods and services in each country. Our "basket" is a McDonald's Big Mac, which is produced in about 120 countries. The Big Mac PPP is the exchange rate that would mean hamburgers cost the same in America as abroad. Comparing actual exchange rates with PPPs indicates whether a currency is under- or overvalued.
Of course it's a rather expedient snapshot of the global economic condition, but I think it's still very illuminating.
As of their most recent posting, the euro and Norway's kroner, among others, is over-valued with a Big Mac costing, in dollars, $5.34 and $7.88 respectively per burger. That is some expensive fast food: by comparison, for those of you who haven't visited your local golden arches, the current cost in the US for a Big Mac burger is $3.57.
In Thailand however (the latest tourist destination du jour amongst all my friends it seems) the dollar is heavily under-valued by some 48% where a Big Mac will only cost you $1.86.