American Customer Satisfaction Index (ACSI). This is an independent measure of household consumption experience. A powerful economic indicator, the ACSI tracks trends in customer satisfaction and provides valuable benchmarking insights of the consumer economy for companies, industry trade associations, and government agencies.

James J. Hill Reference Library: This is an online business reference library that also provides online help by trained librarians. An subscription is required. The annual subscription is well worth the investment to get this kind of information.

Economy at a Glance:  Provides the latest indicators of how the US economy is performing.  All in one place!

Refdesk.com: This is a great site for a wide variety of information of use to managers.  It provides  information and links that are well-organized and useful.  

U. S. Patent and Trademark Office:  If you have questions about current and expired patents, this is the place to look.  Also includes information about patent and trademark rules and regulations. 

Census Bureau:  Provides a range of useful market and industry specific information.  This site is especially helpful for obtaining information about market sizes and productivity.  

Bureau of Economic Analysis:
If you are looking for macroeconomic information (e.g., GDP trends, state-by-state comparisons), this is a good source.  Provided by the U.S. Department of Commerce.  

Office of Trade & Econ. Analysis:  Department of Commerce site.  Great source of information if you are considering moving into international trade or are already involved.  Information comes from a wide variety of sources.  

The Financial Forecast Center:   A whole range of financial data (exchange rates, GDP trends, etc.).  For those who are interested in the dismal science, this is the place.  Very useful information.