Virtually every single end user experience with Office 2010 will involve an improved version of the ribbon user interface that debuted in Office 2007. This includes the traditional Office applications, the Office Web Applications, and even Office servers like SharePoint 2010. Here's the story, from my Office 2010 Special Report:
Office 2010 adopts the ribbon user interface across all applications, and it's an improved version compared to the one that debuted with many Office 2007 apps. Gone is the round Office Orb, replaced instead by a more traditional looking application button that is very similar to the application button that appears in Windows 7's ribbon-based apps, Paint and WordPad. The Office 2010 ribbon also picks up a handy Minimize button--it's the caret-looking thing over on the right next to the Help button--that minimizes the ribbon with one click. You could do this in Office 2007 by double-clicking any ribbon tab, but that isn't particularly obvious.