The Library of Congress at loc.gov has lots of good stuff for research and general learning.
Findlaw.com looks better than megalaw.com.
Constitution.org has a good site for finding historical legal documents, as does Project Avalon (http://www.yale.edu/lawweb/avalon/avalon.htm). The Founders' Constitution (http://press-pubs.uchicago.edu/founders/tocs/toc.html) is also a good site for constitutional history.
Yourdictionary.com is a great site for languages. M-w.com is the site for Merriam Webster Dictionaries. Wordreference.com lets you link to dictionaries with a right click.
About.com is a good way to find out about things -- not necessarily when you want a quick answer, but when you want to find out more about a topic.
The Federal Web Locator: Find anything and everything in the Federal Legislative Branch, Federal Judicial Branch, Federal Executive Branch, Federal Independent Establishments and Government Corporations, Federal Government Consortium and Quasi-Official Agencies, Federal Boards, Commissions, and Committees. GREAT site!