An Australian bank came up with a new way of tracking international currency values using the cost of an Apple iPod as a benchmark.
Previously, the Economist came up with measuring this same thing by looking at the prices of Big Macs all over the world.
And still before that, I remember reading about how another group tied up the price of a can/bottle of Coke to the happiness index of countries. Meaning, that if a can/bottle of Coke is affordable to the citizens of that country, then there's a bigger chance that those people are happy. The suggestion is perhaps that they have more money for food and a little money for things like Coke, which isn't really a staple food. Unless you classify sugar as a staple food.
The Big Mac index isn't too far from the happiness and Coke theory, if we're measuring the affordability of fast food is in certain countries. The cheapest Big Mac to be had is in China -- $1.30, compared with an average American price of $3.15.
The thing with this iPod index is that it's no longer just fast food or a fizzy drink, you're really measuring how much disposable income do countries have when it comes to technology. I'm not sure about the equation "have iPod, am happy."