IPUMS – Minnesota Population Center, University of Minnesota

Various Government Data Sites: Chicago, New York City, San Francisco, Federal

Lots of education data at the National Center for Education Statistics.

World Data Bank

Federal Reserve Chicago and New York

Wisconsin Financial Institutions

Yahoo Finance

Inter-university Consortium for Political and Social Research (requires university membership to access data)

Cash for Clunkers (info link) Data (data link)

Residential Home Sales in Southeast Wisconsin (mid 90s through 2014 available on campus for Carthage faculty/student research)

Google Public Data
Google Trends can be interesting but it’s hard to get actual data from them.

Aswath Damodaran's data suggestions (finance professor at New York University Stern School)