Lindows

If you want to go the commercial route, you may also want to look at
Lycoris. I have seen it in action two times (both demo'd by the Lycoris
president), and it looks nice and easy for a regular desktop OS.

Or you could just use Debian, make sure it is customized to your needs and
then just duplicate it for all the workstations.

Jeremy C. Reed
http://bsd.reedmedia.net/