Search Engines and Directories:
Hotbot   Preferences let you limit results by country, region, domain, URL, or language.  A text-only display is also available.
ipl2    Merger of Internet Public Library(IPL) & Librarians' Internet Index (LII)
Alltheweb    Promises sophisticated search options and deep coverage
Metacrawler    Search several search engines at once here.
Ask Jeeves    Try this UK (British) site offering searches and many other features
Bing           From Microsoft
Twurdy     Scans search results and shows approximate reading level to help you find easier or more challenging text.
For Elementary Students:

YahooKids  (formerlyYahooligans)
AskKids   Designed as a safer, age-appropriate place for 6-12 year old searchers.
updated 21 Feb 2011