Oh, did we forget to mention that HP runs Debian on their BladeSystem – here's a small notice about it.
Read it here
Small: Last fall we introduced support for Debian because we had started to see a lot of deployments on that OS. With Debian support, we've picked up several large enterprise customers outside of North America, especially in Germany. It's a sleeper operating system, and no one has been tracking it like they track Red Hat and Novell. It's just not as visible. But a wide array of customers all across the world have been deploying on it. We are trying to tap into that and we're pretty bullish on our chances.