Debian is a preferred Linux distribution, that's used primarily on PC's, but a lot of 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 consequence of the fact that Debian is developed and supported by countless qualified volunteers all around the world, so any patch which is needed to fix a particular issue is released in a matter of days. The same community will also help you with any question or trouble which a user may ever experience, since they can be contacted via email 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 created 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 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 as well as the 30.000+ software packages that are available for it.