Meta Sites (Listings of Research Tools)

Virtual Salt
http://www.virtualsalt.com/search.htm

A comprehensive meta site (collection of links to other sites) that includes

Search Engines
Google, Ask, Alltheweb, Web Wombat, Altra vista, KartOO, MSN Search, HotBot, Go Network, Zapmeta, Excite, Turbo10, Lycos, Dogpile, Starting Point, Clusty, SearchEdu.com, Zuula

Directories
Yahoo, Looksmart, Google Directory, Open Directory, about.co, 1UpInfo, Librarians Index, Search.com, Education Index, Webbrain,UniXL, 100Hot.com, Planet Search, 100Hot.com.

Reference
Britannica, Encyclopedia.Com, Encarta Online, AllRefer, Free Internet Encyclopaedia, Directory.net, Bartleby, Refdesk, whatis?com, www virtual library, Dictionary.com, M-V.com, Onelook Dictionaries, AcronymFinder, Informine, Essential Links, All Words, SciQuest, English Dictionary, The Way Back Machine, Stanford Encyclopaedia of Philosophy, Wikipedia, The Free Dictionary

Databases on the invisible web (not accessible to ordinary search engines).
FindArticles.com, Magportal, Complete Planet, All Academic, Online Books.

Graphics
Ditto.com, Internet Archive, Marine Art,Google Images, Foto Search, Barewalls.com, Art.com, The Louvre, US National Gallery, Gallary of Art US, Gallary of Art London, Artcyclopedia, PLC Maps.