The PDC is on at the moment so Microsoft have opened the floodgates, Channel 9 is overflowing with cool new videos. Bill Gates' keynote is now available, it's just short of 3 and a half hours but has some very cool stuff some of which also shown in the videos below.
On the Channel 9 front:
Office 12! For someone who uses Outlook and rarely uses Word, sometimes Excel I can never find more complex stuff, everything is buried under these menus that explode everywhere on the screen and it takes a good few minutes to find something, if at all. I suspect this is true for the vast majority of Office users, there's just so many features and it's pretty hard to find them unless you use Office constantly.
Check out the new UI for Office 12 at Channel 9. That is just totally awesome, the fact it previews everything to without making changes to the document is simply amazing. Screenshots now on Microsoft's site.
Also a really cool demo of the Windows Presentation System (formally Avalon), involving Internet Hearts having a new UI bolted onto it, that's totally cool, especially the little bit with putting actual videos onto the cards, that's a brilliant use of Avalon.
If you want to play around with some of the new WinFX stuff today you can do that. Check out Microsoft "Max", works on Windows XP SP2 it'll install WinFX beta for you and you can play around with a demo application that shows off these new interface and communication technologies.