Debian is a widespread Linux release, which is used primarily on PC's, but lots of people have started using it lately as a web server Operating System as well, because of 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 worldwide, so any patch that is necessary to fix some issue is released within a few days. The very same community can also help with any question or trouble which a user may ever have, due to the fact that they can be contacted via email using e-mail lists and a competent response will be sent in no more than 15-20 min. The advantage here is that all your questions will be responded to 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 will not 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 as well as the 30.000+ software packages that are available for it.