Doc and Dave and David are talking about operating systems. I somewhat take issue with the fact that the base OS is commoditized; OS issues are still quite relevant.
Bottom line: if you care about getting software out to your users as quickly and as broadly as possible, the code beneath you that you can leverage makes a world of difference. When it comes to time and money, leverage counts. It's not a commoditized environment: things like the choices of OS, tools, and environments like .NET do indeed matter.
But that's just my opinion. [Ray Ozzie's Weblog]