Government Sites:

General Goverment - Federal and State:

Frequently Used Sites - Popular government related sites arranged by broad categories.

Library Of Congress

Govspot - Commercial site linking to international, federal, state and local government sites.

National Archives & Records Administration

Federal Reserve Board

Business and Commerce:

SBA Small Business Administration

Business Advisor

Commerce Business Daily

GovernmentBids.com

U.S. Patent And Trademark Office (USPTO)

U.S. Copyright Office

Census:

U.S. Census Bureau

American Fact Finder

U.S. Historical Census Data Browser

Elections:

Candidates & Elected Officials For Your State
  Special Interest Groups Data

Federal Forms:

Forms >From The Feds

Applications For Federal Employment

Housing:

HUD Homes And Communities

Money and Taxes:

Bureau Of The Public Debt

U.S. Securities And Exchange Commission

Savings Bonds

Savings Bond Wizard

Regulations:

Code of Federal Regulations

Regulatory Information Service Center

Regulations.Gov

Seniors and Social Security:

Social Secuity Online

Access America For Seniors

National Institute On Aging

Statistics:

FedStats

Bureau of Labor Statistics

Student Resources:

Students Gov

FirstGov for Kids

 U.S. Government For Kids