Yesterday, I attended an event arranged by Microsoft Denmark, with the title "Hvad byder fremtiden for HTML5, Silverlight og Flash?" (in english it's roughly: "What does the future bring with regards to HTML5, Silverlight and Flash").
Somewhere in the middle of the presentation of Silverlights future by Daniel, the conversation turned to whether we're going to need an Operating System in the future or not. I probably should have made the note, that all our devices today have an operating system out of necessity, as it is the glue between all the apps we use, and the underlying hardware, and that is probably not going to change anytime soon. But the notion of the presence of an operating system, may very well be hidden more and more away, until the consumer will not notice it at all. The iOS devices today is probably showing us the direction, in which consumer OS's is going. You actually only notice the OS, when it has to be updated, and when the device is booting or shutting down. All other interaction with it, is through some kind of app.

As a professional user of computers, I personally would hate to loose the OS interaction I have today, as many other professionals would. So this change, or refinement if you will, has to be on consumer-directed OS's.