Yeah, I think in 10 years desktops will be rare, even now they are dying everyone wants portability, look how cheap notebooks have gotten in the last 5 years. Everything will be going into the cloud. We will be using low power portable computers and be accessing everything on the internet. If company's like OnLive actually end up working, gaming people won't need powerful desktops or notebooks. Or even consoles really, I think they will end up dying too, Game developers really don't like have to develop games for 4 different platforms. If everything is going into the cloud, OS does not matter, I can't wait to see what company's like Microsoft will be like in 10 years.
*Edit* Man If OnLive actually works, what won't they be able to do, imagine just renting software like autocad, photoshop, soldworks and having it with in seconds working right there on a low power cheap computer.