Debian is a well-known Linux distribution, that is used primarily on PC's, but lots of people have begun using it lately as a web server Operating System too, due to the stability and security it provides. The latter is a direct result the fact that Debian is developed and supported by thousands of qualified volunteers all around the world, which means that any patch which is necessary to fix a particular issue is released within a few days. The same community can also help with any question or issue that a user may ever experience, since they can be contacted through e-mail using mailing lists and a competent response will be sent in no more than 15-20 minutes. The advantage here is that all your questions will be responded to by the same people who have created the Operating System itself and they have a detailed knowledge of how it functions. As Debian is provided for free, you won't need to pay any license fees to use it and you can personalize it as much as you want or need. This is valid for the Operating System as well as the 30.000+ software packages which are available for it.