According to Russian forum Winreview, Microsoft has passed Milestone 2 which means it's on it's way toward Milestone 3. Build numbers also show this, where builds 78xx are supposedly under the Milestone 1 umbrella, with 79xx builds under the Milestone 2 umbrella.
Microsoft are obviously hard at work on the successor to Windows 7, Windows 8 is early in development but is meant to include some very cool stuff like support for USB 3.0, Bluetooth 3.0, facial recognition, stereoscopic 3D, instant on booting, HID, accelerometers, proximity sensors, hard drive encryption, GPS integration, as well as a strong focus on boot time, shut down time, and battery life.
Rumors have also included two user interfaces, a new push for PC gaming (hopefully!) and a sneak peak at CES 2011.