Microsoft Corporation wants computer science to be taught in UK Elementary Schools. This is a good idea; preparing children for the use of Microsoft office and Windows, but they would not learn UNIX or Linux operating systems, which I believe is key to a well rounded education in computing science. With Linux; you can install Kdevelop and practise programming for free, without the cost of the Windows software like Visual Studio. But with Linux skills in high demand it would make sense to teach Linux or UNIX as well as Windows skills. With the advent of the Powershell, Windows is becoming a more powerful desktop operating system, but for servers, Linux still dominates that front. So it would be important to teach Linux skills at schools to better prepare students for the workplace. Not all systems administration involves the use of Windows Server 2012. Linux and even UNIX operating systems are prevalent as well. A Rasberry Pi is a good way to learn how to use a Linux distribution with a small but extensible computer that can perform many useful tasks. It is powerful enough to run Quake3 and it can run a Linux desktop admirably. Better to use Tint2 and Fluxbox rather than KDE or Gnome though. But that small computer has HDMI output and can store the operating system on a removable SD card; this would provide more than enough space for a single Debian installation. There are downloads available here: http://www.raspberrypi.org/downloads that are Linux images that you can put on an SD card and then boot on a Rasberry Pi to get a fully working Linux installation without much fuss.
These devices would be a very good learning tool for students to play with and in the process they would learn a great deal about using a Linux distribution and the shell commands that are integral to making the best use of your system. Linux is very popular right now; with the rise of Ubuntu and Linux Mint there are very secure and stable alternatives to using Windows on every desktop. But Microsoft are pushing their operating system into schools wherever they go. You can use Cygwin on Windows to get a Bash shell and Linux software running; but it is better to use an actual Linux distribution. Then you will learn far more about how to maintain the system and how to install updates and compile your own kernel from source as well as installing software and making good use of the system as a web server, or just as a desktop machine for day-to-day use. Linux is very good as a desktop operating system due to the fact that you can install whatever desktop environment you wish to make your work with Linux as fun and productive as possible.