Osteopathical Center with 16 employees. We have one Debian server with 10 workstations (terminal clients) and two printers. We use Icedove with lightning extension for our mails and calendars, a homemade GPL python/tk script for our medical needs.
We chose Debian for its stability, security and ease of maintenance. We like Debian as it is totally free and open source, compared to other Debian-based distributions. Thanks to all Debian developers!