I have to apologize in advance for keeping off topic, but I would very much like to clear this one thing. I think that this is very important as there are "under the hood" motions related to Windows 8 that are hidden and not well understood even by many developers (yet), and certainly not by most gamers. Pardon me if this turns out to be a long post, but it is a complex issue. I'll highlight only the most important sentences if you want to skip the details.
Gabe Newel did not overreact. What you don't see here is that, under the hood, the new tiled UI is a means for Microsoft to lock Windows applications into a walled garden, much like the one on iOS. There is this "small detail" that Microsoft is not advertising anywhere, but you can find it dug deep in the developer documentation:
One cannot release a tiled UI application by any other means, but only through Windows Store!
I cannot even begin to stress out just how horrible this idea is! There is no side-loading, except for corporate use inside one company, and that works only on the enterprise edition of Windows 8. Do we all understand what that means? You cannot download an application from the Internet and run it on your computer. You have to get it from Microsoft's store. Even if it is a free app!
If it was just about "being downloaded from Windows store", it would not be a problem. It would be nice to have a common hub to download things from. But to get an app onto that store, it has to be certified by MS. This means bringing the "console experience" onto your desktop. Each app that you will get through the Windows Store will have to adhere to certain requirements imposed by MS. So far, we know that they've banned mature games, like Skyrim, CoD, and Serious Sam.[*] They have forbidden modding. They could very well forbid Open Source if they want. But even if these terms were not there, this is still a certification system. With all of its downsides, including uncertain release dates, rare and late patches, and everything turning out to be more expensive and sucking more.
While, theoretically, desktop applications are exempt from these requirements, it looks more and more like just a foot-in-the-door technique. A large number of developers have expressed their concern with possibility that, probably in Windows 9 or something like that, the ability to get even desktop apps in any other way than through Windows app store may very well be removed. When that happens it will be too late.
I would not invest into supporting the tiled UI apps (which MS now conveniently calls "Windows Store apps" - does that ring a bell?), until MS removes the requirement that they have to be shipped through Windows Store on desktop at least - and thereby remove the requirement of certifying them with MS. Certification is a broken concept and should be abolished.
Now, while in current state Windows 8 do look like they support plain desktop apps seamlessly, the removal of start menu and use of "charms" even on the desktop looks like a pretty blunt attempt to force users to "get used" to the tiled UI. It would be fine by me if it wasn't for the aforementioned certification issue.
So, it is a vicious circle. And not an accidental one. This one was carefully designed to be that way. I say: no thank you, I'll skip on that one.
[*] Yes, I know that the PEGI-16 limit is supposed to be lifted to PEGI-18, but this is only an announcement, and we didn't see the new terms yet. There could still be another fly in the ointment. Note that besides the bare rating, they also disproved profanities, drug references, and various other things like that in terms that are separate from the rating requirement. If they don't remove all of that, a game may satisfy the ratings yet still fail the cert. Worst thing is for such things you simply cannot know what they will allow until you submit, which is terrible.