I just created a search engine using Google technology. Rather than searching every site and page on the internet, PolicySearch ignores non-credentialed pages and searches through all (somewhere in the neighborhood of 85 websites) of the major think tanks (the Cato Institute, the Brookings Institute, etc), several major newspapers and magazines (the NY Times, the Washington Post, etc) and encyclopedias (Wikipedia, for example).
You get all the benefits of Google -- just without having to wade through the spam. Check PolicySearch out. :)