IT, Geodata Danmark, Denmark
We are running about 12 Debian servers, in the past we used different distributions, but in the end we chose Debian for the stability and ease of maintainance. Furthermore we are a strong believer in Free Software.
We run: Xen, apache2, PHP, tomcat, samba. The servers are mainly Internet servers for http and ftp. But a few are set up as NAS with samba and NFS.