I must say that the latest server-edition Ubuntu LTS (Hardy Heron) is really great.
I’ve just finished some upgrades from Ubuntu 7.10 for a server (vps), and I can say that the difference is damn great.

The speed, the package management, the process handling and stability are really improved.
I recommend it to everyone who is thinking about “What Linux would be better to install on my next server?”, I promise you, it’s a pleasure to manage such a distro!