A recent question about "Search Engines", got me thinking (ouch).
A list of search engines can be found at http://www.thesearchenginelist.com/
Also , for the mathematIcally minded there is Alpha , by Wolfram ( the developer of MATHMATICA ), to be found @ http://www.wolframalpha.com/
There is also the Dmoz ,( the Open Directory Project ) : http://www.dmoz.org/
And for a new search engine , there is a truly unique one called WireDoo, caution , it is a startup ( in beta ),and it is being developed by M.C. Hammer http://wiredoo.com/global/signup.html