We are using Debian GNU/Linux to run a little server for the department, with internal web pages and shared home directories. The services are to be competitive with the university's own server, which runs a text-only HP-UX without any of the modern instruments and applications (no TeX, old (2.0) navigator, poor termcap support, very poor technical support, no modern shell), so we decided to run our own server. Also the server controls the two departmental printers, serving a lpd and a cups queue.
We choose Linux to grant multiuser and desk-independent access to the users, easier configurability and updating, and totally cost-free solution, and in particular Debian for the extreme stability and availability. Moreover, our cousin department is serving a stable ftp distribution, so it was also a matter of bandwidth.