U.S. Census Bureau (homepage) Links to several broad categories:
Search windows for states, counties, city/town and zip. Census Quick Facts, Interactive maps to visualize census data.
Census QuickFacts, , Population Clock for the USA & World.
Your source for data about population, housing, economics, and geography. Links to 2010 and 2000 Decennial Censuses. Link to 2007 Economic Census. Reference Maps. Census Tracts.
Constantly updated site for the Decennial Census of 2010.
American Housing Survey reports and tables. Most recent data on the American Housing Survey for the past 6 months. Also links to other agencies or organizations which provide American Housing Survey data and information.