I prefer Bing myself. You oftentimes get less results with searches than Google, but the results are more recent & accurate.
Google has a very powerful search engine, but oftentimes, one has to dig through several pages of links to find what's needed, as they don't clean up outdated links often enough, if at all. Their database is massive.
I'm not sure what browsers doesn't have a ixquick plugin to install their search engine, which by chance is excellent also, but it works well with both IE & FF.
Web Of Trust (WOT) is also a search engine, and rates it's links as to safety. It works in both IE & FF. However, sometimes it'll flag a good site as bad. This happens because the members (the WOT users themselves) can rate a website (give feedback). Sometimes, a user gives bad ratings to an otherwise safe site because they're pissed over a purchase (usually buyers remorse).
http://www.mywot.com/
Cat