Who's using Debian?
OKTET Labs., Saint-Petersburg, Russia
Organization type: commercial
Home page link: http://oktetlabs.ru
We use Debian on all servers and vast majority of workstations. 50-100 installations, including virtual hosts. Development servers are used both for embedded SW development and for intensive and rich testing of our and customer products. Infrastructure servers run non-vanila version of Apache with company patches as well as things like wiki, mail, VCS etc.
The main reasons for choosing Debian - simplicity of administration and stable enough stable releases.