Debian is a well-known Linux distribution, that's used primarily on personal computers, still many people have begun using it lately as a web server Operating System as well, because of the stability and security it supplies. The latter is a consequence of the fact that Debian is developed and supported by a large number of qualified volunteers all around the world, so that any patch that is needed to fix a certain issue is released in a couple of days. The same community will also help with any question or problem which a user may ever experience, because they can be contacted via electronic mail using mailing lists and a competent response will be sent in no more than 15-20 min. The advantage here is that all of 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 free, you will not need to pay any license fees to use it and you will be able to personalize it as much as you want or need. This is valid for the Operating System and the 30.000+ software packages that are available for it.