It is pretty funny to see a clueless moron assume I'm a Unix guy. I'm a Windows guy; I learned Unix in the trenches. I currently have, or have had, large servers running just about every major server OS in my data centers at one time or another. Right now, that is mostly Microsoft and Linux. Linux runs on the mission-critical hardware.
Fact: On any hardware you can run Windows on, someone can run Linux. Fact: There is a lot of really scalable hardware that runs Linux but doesn't run Windows. Nor is there any Microsoft product of equivalent scalability. Fact: On any given hardware, Linux, FreeBSD, and a few other operating systems have superior operational reliability. Unix may not be easy to use for the point-n-drool crowd, but I'll be damned if it doesn't work every time.
I need systems that work, absolutely positively every time. The old Big Iron companies were a little expensive in the bang for the buck department, but Linux largely fixed that. To reiterate a point I made earlier: No version of Windows, Data Center or otherwise, has ever been able to reliably stay fully online 24x7 for years on end in my experience. I can buy this kind of reliability on the same hardware. So exactly why should I use Windows again? Where we use it, it is largely because we have no reasonable alternative.
Clue phone for you: Windows Data Center Edition runs on custom high-end hardware. You can't buy Data Center Edition separately. It's a package deal with the hardware platform, and it comes with uptime guarantees that will more than match whatever your overpriced contracts with Sun and IBM are providing.
Sorry buddy, I have some of that hardware. Yeah, the hardware is great, but what about the software? We do better than five-niner uptime on our Linux systems, the FreeBSD network cores run essentially forever, and our database servers pretty much just run. My problem isn't the hardware, but the software. Constant patching of any type is not an option because our systems can't stop (note: this is my biggest complaint with Oracle -- all the bloody patches).
The fact remains that of all the hardware and operating systems in our data center, the Microsoft ones have the worst uptime and require the most hand-holding. It has nothing to do with the hardware. Even most of our cheesy and cheap hardware runs for years without failure.
When Windows runs as rock-solid as Linux (or Solaris, or half a dozen other OSen), maybe we can talk. But until then, you can thank your lucky stars that the US infrastructure runs on something OTHER than Windows. Windows Data Center Edition is only "good" compared to other versions of Windows. It is still playing catch up with most of the rest of the operating system universe.