Debian is an Operating System which uses the Linux kernel. Though it is usually installed on desktop computers, it's being used on a growing number of web servers too. The reason is that it's very stable, so a server running it will not have to be restarted for months. Debian is also considered to be among the most protected Operating Systems to choose from, due to the fact that security patches are released within days after a problem is discovered. This is possible because thousands of experienced developers work for the Debian project on a voluntary basis and not only do they work on the OS itself, in addition, they provide 24/7 support through special e-mail lists and reply within 20 min to any kind of question. In this light, you will receive top-notch support directly from the developers who know their own platform in depth, and not from a third-party support team. Debian is also one of several Linux distributions with the highest number of packages - over 30,000. Since the Operating System is completely free to use, you will be able to modify both the core as well as all of the packages in the way you see fit. Also, you will not have to pay any license fees.