Securities & Exchange Commission EDGAR
Search filings for public companies such as their 10-Q, 10-K, proxy and 8-K. Allows you to perform a full-text search going back 4 years.
This is the source that all company databases use to get information on a businesses, expenses, employees, segmentation and other aspects of public companies.
American Factfinder
Census data for various geographic areas. Includes population, housing income, race, poverty, businesses and much more. Very easy to use; simply enter the city name and click Go.
Data.gov
This is a data search portal for data sets. Simply enter a topic and you will get results that provide the site location and the filed type (excel, html, pdf etc).
Bureau of Labor Statistics Data
List of resources and data files by the BLS that includes such topics as time-use, salaries, consumer spending, injuries and other labor-related subjects. Most of the data is exportable into excel files for you to download.
Economic Indicators
The Economic & Statistics Administration compiled all the economic indicators, their most current releases and the historical backfiles for you to download. Indicators include stats such as retail trade, residential sales, GDP, home ownership rates and other macro-level statistics.