Unsurprisingly, based on StatCounter GlobalStat data gathered from August 9 to September 1, 2010, Google is still the most used search engine in the world today -- by a clear mile.
During the given period -- across the planet, of the millions upon millions of times that a search engine was used to get to a site with a StatCounter code, a whopping 90.59% of the time; Google was used. (This percentage also represents Google's search volume market share for the said time frame.) Meanwhile, Yahoo got 4.4% market share while Bing - despite Microsoft's marketing efforts - only got 3.53%.
These stats are based on aggregate data gathered by StatCounter given a sample size exceeding 5 billion pageviews per month and collected from across the StatCounter network composed of more than 3 million websites.