If you're running the Beta 2 build of Office you probably want to patch it with the Technical Refresh Microsoft just released a few hours ago, especially if you're running Windows Vista. Some improvements include:
Improved support for the minimized Ribbon
Visual redesign of the "Northwest" corner of the programs
Double-click the Office Button to close the window
Silver color scheme
Redesign of the PowerPoint Home tab
Improvements to default styles for all objects
Quick Customize Menu
New product icons
Usability improvements to the Office menu
Send button in the form in Outlook
Over 1000 changes (most minor) to the content of the Ribbon