This is great news and actually makes alot of sense! Correct me if I'm wrong but the 360 itself runs on the DirectX9 backend anyway and a variant of the NT kernel. So there is little from preventing 360 games running on PCs. Marketing wise this also makes alot of sense, they push the 360 games onto a market they already have a large part of, now to anyone saying:

"But what's the point, nobody will buy 360 anymore"

Well I'm sure they will still be some people who will buy them just because they most likely don't have a powerful PC in their living room. XBOX Live can easily adopted with a PC client, they can still milk for gold access and online play, crossplatform would be a good boost for the community and lastly, by the time Windows 8 is released for the general public it's speculated that the 360 will only have 2 years left at best.

So when the next XBOX is released Microsoft can still milk the heck out of 360 games and I finally can enjoy games like Ace Combat and DoA on my PC without the hassle of reconnecting my 360 instead of my PS3

Good one Microsoft is this is true!