Steven Sinofsky posted in his latest entry how Windows 8 will minimize restarts after automatic updating in Windows Update

Before the Internet, updates such as service packs and "patches" were impossibly hard to come by. You ordered upgrade "media" or maybe bought a magazine with a CD in it. Of course, the Internet changed all that. In fact, when ftp.microsoft.com was first set up, among the first services was the ability to get updates for MS-DOS and Windows. With the introduction of Windows Update, we invested heavily in building not just a software delivery service, but a commitment to delivering high quality updates in a timely manner. It took some time to get to the point where customers trust these automatic updates, and we're proud of how far we've come. Today Windows Update is one of the largest services on the Internet by several measures, and of course we're using Windows 8 development as a chance to improve the experience of product updates too. This post was authored by Farzana Rahman, the group program manager of our Windows Update group.

  Minimizing restarts after automatic updating in Windows Update