We're number 23! We're number 23! U-S-A! U-S-A!
Below is a map that measures the happiness of all the world's countries. (Hilariously, two-thirds of the Axis of Evil are not represented.)
An article discusses the methodology behind the study. Of course this is clearly subjective on many levels, but the results are not entirely unsurprising.
What I'm most interested in are deltas between bordering countries. Like Russia/Mongolia, Spain/Portugal, Israel/Israel's neighbors, etc.
And clearly there's something going on in Scandinavia that I'm totally missing...