However, the intrinsic question of what happens when Microsoft continues selling their products in the EU in what has now been ruled an abusive fashion hasn't been settled. The next step, hopefully, would be for the EU to simply ban Microsoft's operating system altogether since they have refused to comply. This would be a rather larger blow to Microsoft than it would seem at first glance. While being prevented from "collecting the Microsoft tax" in all the countries comprising the EU would obviously be a significant loss of revenue, in the long term what would really hurt MS is the inevitable large-scale adoption of Open Source / Free software to fill the void.
The biggest advantage to Open Source isn't necessarily the obvious one either - undoubtedly, a lot of that missing Microsoft revenue will get funneled into funding new Open Source development, and that's a very good thing. But in the long run, the critically important gain would be the addition of millions and millions of users to the desktop as well as the server side. Open Source development is aided by cash, but it's truly fueled by the presence of users and developers-who-use - the presence of lots of software "itches that need scratching", in the words of Eric S. Raymond and many others.