Oliver O'Brien and Pablo Mateos' superb Census Profiler
While reading Daniel J Lewis' blog on Geography and Info Visualisation (which is superb by the way), I came across this excellent census data and map visualisation by Oliver O'Brien and Pablo Mateos - Census Profiler.
I've been playing around for the past few months with some of the recently opened government open data sources including data.gov, data.australia.gov.au, data.gov.uk and Protovis which I'll share shortly.
A list of the official government data sites around the world can be found on the Guardian's Data Store site including the The Guardian's Data Store Global Development
and a few mashups