Office 2010 (Windows): While the look of Office 2010 hasn’t changed much from 2007, its feel and navigation has certainly improved.
For more information on what’s new in Office 2010 visit: http://www.microsoft.com/office/make-it-great/en-us/whatsnew.aspx
Office 2011 (Mac):
Outlook users rejoice!! Outlook is now available in 2011.
For more information on what’s new in Office 2011 visit: http://www.microsoft.com/mac/word/whats-new