There has been lots of discussion about the web as the new platform so none of what I am saying is new. However, I recently came across Adam Bosworth's take on this which is quite interesting given his experience at Microsoft, BEA, and now Google.
The platform of this decade isn't going to be around controlling hardware resources and rich UI. Nor do I think you're going to be able to charge for the platform per se. Instead, it is going to be around access to community, collaboration, and content. And it is going to be mass market in the way that the web is mass market, in the way that the iPod is mass market, in the way that a TV is mass market. Which means I think that it is going to be around services, not around boxes. I postulate, still, that 95% of the UI required for this world will be delivered over the browser for the same reason that we all still use a steering wheel in a car or have stayed with << < | > >> for so long. Everybody gets it. But this will, by definition, be an open platform because the main value it has is in delivering information and communication. Notice that the big players, Amazon, eBay, and Google have already opened up their information through Web API's. It is Open Data coupled with Open Communication built on top of Open Source that will drive the future, not Longhorn.
The Microsoft/Google wars will be a great one to watch over the years. I, for one, being a big fan of the ASP and hosted software model, like the browser based-platform. It makes so much sense and will continue to do so as we get even more bandwidth and more devices from which to access web-based services. As GBrowser rolls out, I wonder how long it will be before Google, leveraging open source, rolls out GOffice and GCollaboration (web-ex like functionality) to really go after Microsoft. Maybe Salesforce.com and Google get together at some point in the distant, distant future?