Microsoft did a great deal of user-interface overhaul in Internet Explorer 9 and the same trend might get continued in future version of Internet Explorer (Internet Explorer 10) as evident from the freshly leaked web-browser screenshot of "Windows 8 Internet Explorer".

Possible Internet Explorer 10 User Interface

Apart from this, Microsoft will apparently also include their own PDF reader in Windows 8 called "Modern Reader" which utilizes the popular "Windows Phone 7" Metro UI and is based upon the upcoming Windows AppStore AppX.

Windows 8 "AppX" Application Package - Modern Reader

Via : Winsupersite