Windows Vista Service Details
Allows users to log in to this computer. Not required to make outward connections with Remote Desktop. It may be required to use the new Vista features of terminal services, which allows you to run remote programs without being 'conscious' of the use, as it will run in your own desktop, rather than through a Window. I will get around to investigating this further...
Allows multiple users to be connected interactively to a machine as well as the display of Desktops and applications to remote computers. The underpinning of Remote Desktop (including RD for Administrators), Fast User Switching, Remote Assistance, and Terminal Server.
Consequences of Stopping:
I believe that Terminal Services to a computer are disabled by default, unless you set it up, so I am unsure why this process needs to be running at all times.
All services listed in 'Required For' will be unable to function
Windows Media Center Extender Service, Terminal Services UserMode Port Redirector