Ubuntu is a very popular OS, that uses the Linux kernel. Though it is used mainly on desktop machines, its server version has been rising in popularity recently as well. Ubuntu is one of the lightest Linux releases available and it supports almost any hardware, which makes it a universal Operating System. It is also very stable and secure and has an at the very least a 5-year support life cycle, so you will be able to get official security and performance updates. Unlike numerous other OS's, Ubuntu is distributed without license fees and you will be able to customize its core, and / or all of the thousands of packages it contains, in any way you see fit. This allows you to install the right software environment for all your web apps regardless of their requirements. Because of the popularity of the OS, Ubuntu has large developer and user communities, so that you'll always find find lots of materials on the world wide web regarding any question or problem that you might have.