Debian is a widespread Linux release, that's used primarily on PC's, still many people have started using it lately as a web server OS too, due to the stability and security it offers. The latter is a result of the fact that Debian is developed and supported by countless qualified volunteers internationally, so any patch which is necessary to fix a certain issue is released within a matter of days. The same community can also help you with any question or problem that a user may ever encounter, because they can be contacted via electronic mail using mailing lists and a qualified response will be sent in no more than 15-20 minutes. The advantage here is that all your queries will be addressed by the same people who have made 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 will be able to personalize it as much as you want or need. This is valid for both the Operating System as well as the 30.000+ software packages which are available for it.