someone has already said vnc for the remote desktop. i'd add configuring systems for remote admin is practical.
some sort of network inventory tool. we've hacked the data from this into our own little db which has been invaluable:
network inventory navigator
very handy for cataloging just about anything regarding your PC's. software, hardware, drive space, etc..
some sort of centralised control and reporting for antivirus software. (i've only used McAfee products for a long while now, their ePolicy Orchestrator hooks itself into other vendors products)
a proxy server for web access and removal of external access to port 80, with log monitoring to see who's trying to use im/kazaa etc..