In the past, since Google Maps launched, a search that was address or location specific, may have brought up a Google Map result, which also contained links to other mapping services, such as Yahoo! Maps and Map Quest. Those links have now been removed and now Google only shows a link to Google Maps.
Greg Sterling at Search Engine Land received a statement from Google on the matter:
"Google is always working to improve search. The redesign of maps onebox better simplifies the Google user experience when looking for business and address information. Users will now be able to obtain directions and store their default location."
He wonders when will Google stop showing other financial quoting services for searches on ticker symbols, such as aapl.
Google Blogoscoped has a before and after screen capture for san francisco.
Forum discussion at WebmasterWorld.