Something that Windows users have been annoyed by for many years is the "You must restart your computer for the changes to take effect" nonsense. Luckily, Microsoft understands how frustrating this can be and it appears that with the release of Vista, something other people take for granted will now be a part of the Windows experience as well. "Restart Manager" in Vista will allow the OS to update many components without rebooting. Microsoft hasn't spoken much on this feature, though they certainly should - daily reboots can be troublesome, especially in large environments.
It apparently works as a system service. The Restart Manager will be able to stop certain parts of the OS for update purposes, update, and then start it again, seamlessly. No reboots, no fuss. Not only that, but if a reboot is required, it is possible for the OS to take a snapshot, similar to hibernation, of the current system state. This would allow it to be restarted and brought back to where you formerly were, documents and programs ready. As a system admin I often take for granted the ability to update nearly every component without ever requiring a hard reboot, which affects both server stability and user experience. Being able to also do Windows program updates and core component updates without having to reboot users would be a boon to both home and office.