Debian is an OS which uses the Linux kernel. Although it is usually set up on personal computers, it is being used on more and more web servers too. The reason is that it's really stable, so a server running it won't have to be restarted for months. Debian is also regarded as being one of the most safe Operating Systems out there, because security patches are released within days after an issue is discovered. This is possible since thousands of well-experienced developers work for the Debian project on a voluntary basis and not only do they work on the OS itself, but they also provide 24/7 support by using special mailing lists and respond in 20 minutes to any kind of question. Thus, you'll have top-notch support directly from the developers who know their own platform in detail, and not from a third-party support team. Debian is also one of several Linux releases with the highest number of packages - more than 30,000. Since the Operating System is completely free to use, you can modify both the core and all of the packages in the way you see fit. In addition, you will not have to pay any license fees.