I think there is no doubt about the fact that google is the most popular search engine . In fact every newbie might be thinking of it as the only search engine available . Here in many asian countries especially India , with rising broadband population google is a fashion fad and everything unknown is put up on google . The popularity of blogs based on their ramblings with google also ensures that the google popularity is unprecedented .
Although here is a good link for the top spots in US :
http://www.high-search-engine-rankin...ch_Engines.htm