Today, Microsoft will be launching Windows 8, the biggest redesign of its flagship product in nearly two decades; making October 25th 2012 a pivotal moment, not just for the world's largest software manufacturer, but for the tech industry as a whole.

Windows has been the dominant operating system for decades, and has enabled Microsoft to play a disproportionately large role in shaping our digital lives. However, this dominance is largely maintained by legacy versions and uptake of new releases has been declining for some time.

According to Steve Brazier, CEO of research firm Canalys, desktop usage is around 72% of the global market, down from more than 95% at its peak. However, if you include mobile devices, Windows' share plummets to just 32%. Of course those figures are relative, there are physically more Windows users than there were ten years ago, but only due to the overall increase in the market.

That 32% is the reason Microsoft have chosen to pursue device agnosticism with Windows 8. Attempting to create an holistic experience across all devices that they hope will revive their flagging fortunes. Unable to achieve this in a single product, they have chosen to release two flavors of the OS: Windows 8 and Windows RT.

The former is largely aimed at desktop usage, able to run all the applications you would expect and performs well in bench tests, but destroys battery life. The latter has reported problems with tasks as fundamental as playing HD video, but is far more efficient making it best suited to mobile devices.

Microsoft's Windows has always been a less innovative product than Apple's MacOS; where it succeeded was in opening up development to third parties. There was a time when it was rare to find any software other than high-end design applications for MacOS — something that is no longer the case — whereas Windows users had their pick of countless freeware, shareware and more polished options.

It might seem strange therefore to see Microsoft taking a couple of leaves out of Apple's book: firstly they have released dedicated hardware to run Windows 8 & RT; secondly they have launched an App Store to enable them to restrict the applications that can be installed on Windows RT — Windows 8 will allow you to install applications just like previous versions of the OS but on Windows RT you will not be able to install anything that does not come through the store, and that includes alternate browsers and plugins.

Industry experts have been confidently predicting for some time that Microsoft must deliver a successful tablet or experience a terminal decline. It is ironic then that the software giant who always outsourced its hardware appears to have delivered a winning tablet with its new Surface, crippled by a poor OS. The touchscreen interface is reported to be very good, however the screen has poor resolution (1366x768px compared to the iPad's 2048x1536px). There is weak app support (4,000 compared to the iPad's 275,000). Many apps are apparently crash-happy. The one major issue with the Surface hardware is that there's no 4G, or even 3G, it's a mobile device that only connects via wi-fi.

It's hard to shake the feeling that Microsoft developed Windows 8 through a desire to innovate, only to hobble it with Windows RT because they felt they had to; either because they couldn't make Windows 8 efficient enough to run on a mobile device (even their own) or because the uber-control extolled by Apple is the proven route to financial succes and market dominance.

Despite this reservation, and in spite of the 'sink or swim' reviews there's a good feeling surrounding Microsoft right now. For the first time in many years — if ever — they've attempted to innovate instead of imitate. And while Windows RT looks like a flop, its big brother may be capable of interesting new users without alienating the old. In my mind Microsoft were always The Empire, it turns out they might be the Rebel Alliance after all.

Are you a fan of Windows? Will you be upgrading to Windows 8 or Windows RT? Let us know in the comments.