Thanks fuck for that.
Cost is important everywhere. And you have to be careful with what your costs are.
From my experience in deploying a number of simple machines, Windows license costs are the least of worry. There's the cost of installing Windows - a PITA when compared to being able o PIXIEboot a new machine and install an image. I can commision a Linux box in the time it takes for Windows to boot the install media.
NHSubunt should just deply a simple GUI desktop, and shove all the logic behind a web browers.