There is a lesser known search tool in the search engine category called Answers.com. This engine stands out from the pack due to its content. What makes them different? They started with 180 authoritative titles purchased from reference publishers and then added patented database technology, to provide very informational pages on a subject. There are also original articles from Answers.com's in-house editorial team as well as Wikipedia content.
For other alternatives to Google, check out the Internet Search Tools category on the MPL home page under the category of Recommended Links.