Debian is a well-known Linux release, that's used mainly on desktop computers, still lots of people have started using it lately as a web server OS as well, because of the stability and security it provides. The latter is a result of the fact that Debian is developed and supported by a large number of qualified volunteers internationally, therefore any patch which is required to fix a particular issue is released within a couple of days. The very same community will also help with any question or trouble that a user may ever encounter, since they can be contacted via e-mail using e-mail lists and a qualified response will be sent in around 15-20 minutes. The advantage here is that your questions will be replied by the same people who have developed the Operating System itself and they have an in-depth knowledge of how it works. As Debian is free, you will not need to pay any kind of license fees to use it and you'll be able to personalize it as much as you want or need. This is valid for both the Operating System and the 30.000+ software packages which are readily available for it.