Some websites aggregate multiple sources of data together. We like these sites, and the people that have made them. Here are some that we have found.
Social Science Electronic Data Library: "600 premier data sets and 275,000 variables"...have fun! Nice search features too.
Data on the Net: listing of 363 Internet sites of numeric Social Science statistical data, data catalogs, data libraries, social science gateways, addresses and more.
Fedstats: A website that collects data from 100's of US federal, state, and local agencies.
Resources for Economists on the Internet: Literally, this is what the site is called.
The Data Mine: CQ Roll Call's multimedia blog which features interactive visualizations of US government and congressional data along with in-depth, policy-oriented analysis of the latest facts and figures
Collection of Environmental Data: Lots of data on different aspects of the environment, mostly for environmental economics.
Collection of Economics and Finance Data: Varied types of data, much of it for macroeconomics and finance purposes.
International Economics Statistics: Varied types of data on international trade, growth, etc..
Health data: Varied types of data on health, including US and International data
Historical Statistics of the United States: Provides data on demographics, politics, & economics in the United States from the colonial period until now.
International Trade data: Varied types of data on international trade
LexisNexis Statistical Insight: This is Lexis Nexis's statistics database. Click open optional user profile in upper left corner to create a user profile.
International Relations Data: Paul Hensel provides a useful assortment of data on international states, alliances, geography, conflict, cooperation, economics, the environment, politics, and social issues.