Microsoft blogger Steven Sinofsky reveals some details about Windows 8's classic desktop and the new Metro style user interface, you can read it over here.
We believe there is room for a more elegant, perhaps a more nuanced, approach. You get a beautiful, fast and fluid, Metro style interface and a huge variety of new apps to use. These applications have new attributes (a platform) that go well beyond the graphical styling (much to come on this at Build). As we showed, you get an amazing touch experience, and also one that works with mouse, trackpad, and keyboard. And if you want to stay permanently immersed in that Metro world, you will never see the desktop—we won’t even load it (literally the code will not be loaded) unless you explicitly choose to go there! This is Windows reimagined.
But if you do see value in the desktop experience—in precise control, in powerful windowing and file management, in compatibility with hundreds of thousands of existing programs and devices, in support of your business software, those capabilities are right at your fingertips as well. You don’t need to change to a different device if you want to edit photos or movies professionally, create documents for your job or school, manage a large corpus of media or data, or get done the infinite number of things people do with a PC today. And if you don’t want to do any of those “PC” things, then you don’t have to and you’re not paying for them in memory, battery life, or hardware requirements. If you do want or need this functionality, then you can switch to it with ease and fluidity because Windows is right there. Essentially, you can think of the Windows desktop as just another app.