Google Probably the worlds biggest search engine. It has a map feature with 'street view.'
Bing Microsoft's search engine. Its map search feature has Ordinance Survey maps for most of the UK.
These are multiple engine searchers: Google, Yahoo! and Bing. They all use the same 'Metasearch Technology.'
DuckDuckGo A search tool that does not collect or share personal information.
ixquick Another search engine that protects privacy. This has an image search option.
Exalead This show thumbnail page previews and has some interesting search features.
Ask Jeeves A question and answer based search engine.
Google Scholar
A couple of academic search tools.
Omgili Searches forums, discussion groups and mailing lists.
Gigablast A 'green' search engine, which has a search directory feature. However, it does not give its privacy policy