Internal IT, Dawan, France
We use Debian on all our remote locations (Samba/NFS/ISC-DHCP/BIND/tinc), on our physical servers and most of our virtual machines hosting our internal services (LAMP mostly). This all accounts for a dozen of servers running on Debian.
We chose Debian because of its ease of use, its openness and its amazing community that delivers overall a stable and nice Linux distribution. Debian is also our first choice when we provide Linux training.