Done this before and i am still wondering what to do with the wp_posts => guid content, which has reference to http://localhost
But at wordpress.org http://codex.wordpress.org/Changing_The_Site_URL it clearly states:
Never, ever, change the contents of the GUID column, under any circumstances.
But as i understand it is just to unique identify your posts globally. But as more people would have http://localhost in their guid.