Debian is a widespread Linux release, that is used mainly on desktop computers, however many people have started using it lately as a web server Operating System as well, 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 around the globe, so that any patch that's necessary to fix some issue is released within a few days. The very same community will also help you with any question or trouble that a user may ever have, due to the fact that they can be contacted via electronic mail using e-mail lists and a qualified response will be sent in around 15-20 min. The advantage here is that all of 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 works. As Debian is absolutely free, you won't need to pay any license fees to use it and you can customize it as much as you want or need. This is valid for both the Operating System and the 30.000+ software packages that are available for it.