I have been using windows since it first launched, and DOS before it. What people on this forum have failed to grasp is that Microsoft have to get their OS tablet friendly, like now as the tablet devices are coming. Also Microsoft don't want to make many different OS's for all these different devices, so they are going to try and make one, Windows 8. This is confirmed by the other big story about Windows 8 that may have been missed here, it will run on ARM CPU's as well as the x86 ones it has run on exclusively up until now. That's big and shows where Microsoft knows the market is going.
But don't get your knickers in a twist over the Metro UI. It is the same as the simple UI that is used for Windows Media Center, as in you don;t need to run it. You will be able to run Win 8 using a traditional Windows UI, Microsoft are not crazy enough to remove that. In fact from the stuff shown at Computex that UI looks exactly the same as Win 7.
But I am sure they will do their best, as have been done since 95, to hide away below many annoying menus actually getting at the technical stuff. Every OS since 95 has meant extra clicks to do something like disable and re-enable your LAN port.
That is the one thing that annoys me the drive to simplify the OS cause MS are scared of Apple. Why? They have like a few % of the Desktop OS market and that figure has been steady for a while after their recurrence.
Where MS did have to make sure they were addressing, was in the mobile space, where Apple are kicking their butts and I think the Metro interface does this. So Metro looks like it will be great for use on a tablet, better than IOS anyway. And I will see what they are bringing to the traditional UI to see if the upgrade from Windows 7 is worth it on the desktop, but really people take a chill pill.....