Debian is a Linux distribution, that is preffered for desktop machines, yet it's been gaining popularity as a server Operating System over the last few years too. It is really dependable and protected, since fixes are released in a couple of days after a problem is discovered. Debian has a large support community, so if you have any kind of questions or issues with the OS or with any of the 30,000+ packages it comes with, you'll be able to contact the developers without delay via electronic mail using special e-mail lists and receive a reply within 15-20 minutes. The Debian community provides the top level of support possible, because all your questions will be handled by the same people who created Debian in the first place, so they have a thorough knowledge of how their own system operates. Since the Operating System is free to use and distribute, no license costs will be included with your website hosting fees and you'll be able to modify the code files and any other software that you install with no restrictions, so as to optimize the software environment for your web sites. Furthermore, Debian performs really well on any kind of hardware, as it's light and quick and doesn't need a lot of memory.