If we're talking servers here, Debian is incredibly versatile, supports a wide variety of different packages, and rarely requires a reinstall. The cons are that it is not a distribution for non-experts. If you don’t know your way around Linux, I’d strongly advise looking for a different distro on which to run your server. There is also no support, and Debian tends to lag behind a bit in software updates compared to its competitors. Ubuntu's best feature is that it has a unified package repository for all its different versions. This gives it an unprecedented level of versatility, allowing administrators to easily switch between server kernels until they find one that suits them. You could also look at CentOS, which is basically a free version of Red Hat Enterprise Linux – the most widely-supported distribution in corporate IT. It is also the most stable, secure, and hardened community-driven distributions around. This security makes it a very good choice. Check out this post that compares the three. http://www.futurehosting.com/blog/the-three-best-free-linux-distros-for-server-hosting/