Debian is a popular Linux release, that is used primarily on desktop computers, however many people have started using it lately as a web server Operating System as well, because of the stability and security it offers. The latter is a result of the fact that Debian is developed and supported by a large number of qualified volunteers around the globe, therefore any patch which is necessary to fix some issue is released within a couple of days. The very same community will also help you with any question or issue that a user may ever experience, because they can be contacted via e-mail using mailing lists and a qualified response will be sent in no more than 15-20 min. The advantage here is that all your queries will be replied by the same people who have developed the Operating System itself and they have a detailed knowledge of how it functions. As Debian is free, you won't have to pay any kind of license fees to use it and you can personalize it as much as you want or need. This is valid for the Operating System and the 30.000+ software packages that are readily available for it.