enbuenosaires.com, Buenos Aires, Argentina
We are a small property web site based in Buenos Aires, Argentina, currently with around 120,000 visitors a month, and serving around 1,500,000 page views.
We use Debian on our production and development servers, for several reasons: It is extremely easy to install and maintain, the package management is really straightforward. The documentation likewise is very good. We're running apache 2.0, java tomcat 5.5.17, mysql 5.x, qmail and it handles it beautifully.