I gotta say that office 2007 looks pretty sweet
The newer Office 2007 User Interface
Since Beta 1, the Office team has been hard at work refining the new UI. Yesterday they revealed the latest work, and for those of you on Beta 1, you'll notice that things are much more crisp. If you haven't seen any of the screenshots yet, you should check out Jensen's post: http://blogs.msdn.com/jensenh/archive/2006/03/09/547281.aspx
Jensen has a bunch of screenshots and if you haven't been to his site yet, I highly recommend it. He puts me to shame with the amount of content he posts (he posts a new article every day). Here's one of the screenshots from the new Excel UI (notice that a different skin is applied too):
If you're interested in finding out more information about Office 2007, as well as signing up for the upcoming Beta 2, you should visit the office preview site: http://www.microsoft.com/office/preview
-Brian
[Via Brian Jones: Office XML Formats]