Data.gov A tool for finding, accessing and using Federal government data sets, newly developed to promote open government. More About Use
ICPSR Login or create an account before searching/downloading. A depository of raw data sets in the social sciences. More About Use
Proquest Statistical Datasets Requires Java. Almost 600 datasets from government, IGOs, trade organizations, universities and the private sector. Search results downloadable as custom maps, spreadsheets, tables and documents.