It seems like Windows 8 might bring something along that has the same idea as an application store for Windows software

Lets just cross our fingers and hope it does not die after a year of launching and can supply decent software for all users.
There were also a few packages manager prototypes for Windows, but they never really took off, I remember hearing a lot off fuzz win-get and how it would bring apt-get easiness to Windows, but visiting the page now I can see that a lot was dropped since back then and the repository has mostly outdated software.
I also found Npackd, seems decent and the repository has a couple of hundred applications.

And Speed Install

They can help you out installing Windows software and even though they might not be actual stores they are close to a package manager and installer for Windows.
Other than that there are a few known sites out there with services that might be used the same way as an application store: allmyapps.com is one of them but not really an application store as the Ubuntu Software Center.