If you look at the history of personal computing, you'll notice how focus has been moving up the stack. It started with the hardware - the hardware was key, the hardware was where the differences were made. In the '80s, numerous different hardware platforms formed the basis for home computers, like the Mac and the Amiga.
Over time, focus has shifted away from the hardware platform to the operating system where the differences are made. The various different hardware platforms in home computing all lost the battle with Intel's x86, and with Apple ditching PowerPC, this shift was complete. It's now the operating system that differentiates one computer from the other; Windows, Linux, Mac OS X.
And now we're moving even further up the stack. A lot of people seem to think that the operating system as it exists today is becoming ever more irrelevant; it will become nothing but a simple gateway towards applications
on the internet in the cloud. Applications no longer care about what operating system they're running on, much in the same way that operating systems currently do not have to worry about what hardware they're running on.
The hardware part of personal computing has been standardised. It's x86 all the way now. And here is where it gets interesting: because applications no longer care about what operating system they're running on, the hardware platform has suddenly become less relevant and defining too. In other words: the x86 monopoly is now more vulnerable than it has been in a long while.
Because the operating system is becoming irrelevant, people will no longer care about using Windows or Linux, and with that, new opportunities are once again rising for other hardware platforms, such as ARM. Regular Windows won't run on ARM, and with applications becoming ever less operating system dependent, people will be just as happy accepting an ARM machine running Linux as they were with an x86 running Windows.
And this is where the Linux world shines. Thanks to its open nature, it already runs just about everywhere, and a possible ARM netbook revolution will leave Windows in the dust while providing a massive opportunity for Linux to finally gain a serious foothold in home computing.