Paul Thurrott has done a nice overview and preview of Microsoft Office 11 on his site.
He discusses what will be new in Office 11, and the four major design goals for Office 11, which are :- Security, reliability, mobility, and ease of use.
An overview of XML, Office 11 and SmartDocs follows, with most of the Office 11 applications having XML enhancements added to each.
Microsoft Outlook 11 appears to be the most significantly improved product in the suite. New column views for most aspects of Outlook. Outlook 11 won"t display HTML content by default any more. One annoying feature is that Microsoft has significantly changed the menu structure in Outlook 11, some keystrokes that worked in 2000/XP now don"t work in Outlook 11.