Debian
See why a lot of system administrators head straight for Debian whenever choosing an Operating System for their servers.
Debian is a Linux distribution, that's widespread for desktop machines, but it has been becoming more popular as a server OS over the last few years as well. It is very dependable and secure, as fixes are released in just a couple of days after a problem 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 is equipped with, you can easily contact the developers immediately through email using special e-mail lists and receive a response within 15-20 min.
The Debian community offers the best level of support possible, as your questions will be handled by the very same people that built Debian in the first place, so they have a detailed knowledge of how their own system works. Because the Operating System is absolutely free to use and distribute, no license charges will be included with your web hosting fees and you can customize the program code files and any other software that you install with no restrictions, so as to optimize the software environment for your websites. In addition, Debian performs very well on any kind of hardware, because it's light and fast and doesn't need a lot of memory.
