If you already have the Exchange 2007 desktop wallpaper (see previous post), you can also view demos of Exchange 2007 in action in WMV streaming format.
http://www.microsoft.com/exchange/preview/evaluation/demos.mspx
From looking at the demos, the list of new features in Exchange 2007 is pretty extensive, and provides real benefits worth the money. Most of the things that should probably have been there ages ago such as Outlook autoconfiguration and full featured Outlook Web Acess. Also, the RUS is gone, and a good thing too, so now you don’t have to wait for mailbox stamping after creating a user – Exchange attributes are created on the spot.