Probably the most graphically stunning is A Handsome Atlas  from Brooklyn Brainery, with its colorful and imaginative visualizations of nineteenth century census data.

Rich Blocks, Poor Blocks  takes data from the US Census Bureau’s 2007 through 2011 American Community Survey to map  income data on income and rent. Data can be displayed by street address, zip code, census tract number, or city, and comparisons to state medians are also shown.

Bostonography was developed by two “cartography geeks”. It  includes maps on themes such as distances to liquor stores and Dunkin’ Donuts locations.  The site is also attempting to define some of Boston’s disputed neighborhood boundaries by crowdsourcing  “collective definitions of Boston’s neighborhoods by its residents and those who know the city well.”

Gapminder bills itself as  “a non-profit venture – a modern “museum” on the Internet – promoting sustainable global development and achievement of the United Nations Millennium Development Goals.”  Its data page contains visualizations on 513 socioeconomic indicators by country. The same data is also available to download to spreadsheets. The rest of the site is also worth checking out, particularly the Joy of Stats documentary.