Sidney Sussex College, University of Cambridge, UK
Using Debian to provide the College's web server and have been since 1995. Despite temperatures in the non-airconditioned room taking an average of 18 months to destroy the web server, Debian has provided the tools necessary to recover data from the (almost) trashed discs several times. At the time of first installing, the Debian machine replaced a Windows 3.1 web server - which had to be taken off-line in order to update the site. Clearly a great step up.