Debian is a widespread Linux release, which is used primarily on desktop computers, but numerous people have begun using it lately as a web server OS as well, because of the stability and security it supplies. The latter is a direct result the fact that Debian is developed and supported by countless qualified volunteers internationally, so any patch that is needed to fix a certain issue is released within a few days. The very same community will also help with any question or problem that a user may ever have, since they can be contacted through e-mail using mailing lists and a qualified response will be sent in around 15-20 minutes. The advantage here is that all of your queries will be answered by the same people who have created the Operating System itself and they have an in-depth knowledge of how it works. As Debian is free, you will not have to pay any kind of license fees to use it and you'll be able to customize it as much as you want or need. This is valid for the Operating System as well as the 30.000+ software packages that are readily available for it.