Computer Science, Brown University, Providence, RI, USA
Debian is our primary *nix platform, with over 460 desktops and server machines on our department network. We also have a small number of CentOS servers and about 140 Windows desktop machines.
We chose Debian for several reasons, among them: easy upgrades, the large number of packages, well-thought-out package defaults, and stability. With a small staff and demanding community, Debian helps us streamline our support efforts.