Here is a nice thread at Search Engine Watch Forums based on an article by Mary Ellen Bates named Searching for Quick Answers To Odd Questions. I'm just going to list the Specialty Search Engines below as a reference:
Refdesk: good for answering factual questions InfoPlease: good quick fact database Statistical Abstract of the United States: US Census Data HowStuffWorks: this is great when you want to know how to build a toaster or something Internet Movie Database: Movies Quotations Page: quotes Librarians' Index to the Internet: what it says Snopes: Urban Legend References Scirus: The Science Search Engine Internet Archive: archive of historical websites FindLaw.com: Legal Information Resource SingingFish: Owned by AOL (i think) streaming audio or video search engine Find Articles: Article Search Engine eBizSearch: By IBM academic and commercially e-biz articles search engine Search Systems: Free Public Records Directory Cite Seer: Computer and Information Science Papers