At present the idea that Windows 8 will run xbox 360 games is only a RUMOR.
And even if that rumor is true, the so called "console less" emulator is said to be based on a client server model where the client has to have a PAID subscription to be able to do and NOT locale to your PC as stated here (dated July 2011)
http://www.gamespot.com/news/6323247/windows-8-to-play-xbox-360-games
Personally I have no interest in paying an online fee ON TOP of the monthly US$60 to comcast to be able to pay a disk contained game.
Again I just hope 343 decides to include us PC OFFLINE gamers back into the Halo franchise and not abandon us the way Bungie did for the LAST part of the trilogy.