Google is the best search engine. A report from Comscore may vividly clear your doubt
"Google Sites ranked as the top search property worldwide with 87.8 billion searches in December 2009 , or 66.8 percent of the global search market. Google Sites achieved a 58-percent increase in search query volume over the past year. Yahoo! Sites ranked second globally with 9.4 billion searches (up 13 percent), followed by Chinese search engine Baidu with 8.5 billion searches (up 7 percent). Microsoft Sites saw the greatest gains among the top five properties, growing 70 percent to 4.1 billion searches, on the strength of its successful introduction of new search engine Bing. Russian search engine Yandex also achieved considerable gains, growing 91 percent to 1.9 billion searches."