I noticed over at www.Windows8Center.com that they picked up a leaked copy of Windows .Next. Definately some interesting stuff there.
They were showing new push notifications, an improved disk cleanup, new cloud features in there but for me the coolest thing in Windows .Next is the Windows Portable Workspace. From what I can tell, it is Windows on a USB Stick. This will allow you to have your own customized copy of Windows which you can take anywhere with you.
As it stands now, you will need at least a 16GB USB stick and larger if you have stuff you want to have on the stick.
I am sure over the next few months we will see more stuff come out and Microsoft will start talking about Windows .Next as the ship date starts to approach.