Debian is a Linux release, which is preffered for desktop computers, however it's been gaining in popularity as a server OS during the last couple of years as well. It is really stable and secure, since fixes are released within a couple of days after an issue is discovered. Debian has a huge support community, so when you have any questions or problems with the OS or with any of the 30,000+ packages it features, you'll be able to contact the developers straight away via e-mail using special e-mail lists and receive a reply in 15-20 min. The Debian community gives you the top level of support possible, because all your questions will be handled by the very same people that made Debian in the first place, so they have an exhaustive knowledge of how their system functions. As the Operating System is absolutely free to use and distribute, no license costs will be added to your hosting fees and you'll be able to customize the program code files and any other software that you install with no restrictions, so as to optimize the software environment for your Internet sites. In addition, Debian performs really well on any kind of hardware, as it's light and fast and doesn't need a lot of memory.