Network Access Protection (NAP) is of course integrated quite deeply into both products. NAP is the feature that allows you to quarantine machines, preventing their access to the network, if their current security settings don't measure up to a baseline that you, as the administrator, can define.

NAP was designed originally for Vista and Longhorn Server, and while an add-on is being developed for Windows XP, its functionality will be more limited, and the client won't be as manageable as the one built in to Vista.

Windows Vista and Longhorn Server will use a single model for updates. Both Vista and Longhorn Server updates will use the same "core," which makes applying updates a lot simpler and significantly more reliable. As it stands, differing cores on the client and server systems sometimes present troubles, but a patch on Vista will be of the same model as a patch for Server.

The two operating systems together offer centralized monitoring and reporting. Via an event-forwarding methodology, Windows Vista clients can be configured to send all, or some subset of, events occurring on the machine to a central log store on either another Vista machine or a Longhorn Server machine. This allows administrators to see a central view of events and helps them to see trends in problems or information across a variety of different systems.

Client-side caching is greatly improved. If you've been using the Offline Files and Folders feature of Windows 2000, XP and Server 2003, you know that the facility is convenient but not exactly seamless -- you generally have to initiate a synchronization yourself, sometimes writes and reads are slow and so on.