Lycée Molière, Belgium
Being a private school, the Lycée Molière does not benefit from all the State sponsored grants public schools would normally do. Offering to pupils the same quality of teaching as in other schools is therefore sometimes a major challenge.
When it came to provide the common Internet services to the school, the GNU/Linux solution became obvious to us. Our network is made of +/- 30 Macintosh Imacs (still running Mac OS, for the moment at least!) on the workstation side, and of 1 mail server (exim, cyrus-IMAPd and squirrelMail), one web server (apache), one DNS server (bind9), one file server (netatalk) and one proxy server (Squid + squidGuard), on the server side.
As the school is noway in the position to hire a full-time IT admin, all those machines have to be as stable and secure as possible and what other distribution would do that better than Debian?