There's been a lot of debate around web vs desktop as a platform for deploying applications for some years now. With the popularity of web 2.0 initiatives (and social networking sites in particular) some thought the whole momentum was shifting and the very idea of desktop applications was antiquated. Of course that is not the case, there is still the issue of occasionally connected devices, the lack of offline functionality that comes with it and on the other hand the situation where current generation web applications are crippled because of browser and security restrictions.
What is the web 2.0 way to solve this? They release 'desktop' utilities to work around the issues such as drag 'n drop upload, publish 'desktop' widgets to allow interacting with their particular site outside of a browser environment. Do you see the problem here?
Its not a question of choosing between either. Technology like Adobe's AIR (or Google Gears to some extent) are taking on the task of bridging the gap between these two platforms and bring them together. It is the same web application that gets enabled on the desktop, breaking out of the restrictions of a browser shell to integrate seamlessly with the OS file system, a local database (SQLite) and transparently work with system events, notifications, icons, installation across PC, Mac and coming soon Linux.
If you have a HTML, AJAX-enabled web application or a full-fledged Flex application why not package that up as an AIR application and bring it to the desktop. In many cases where not talking about creating a new application, rather just a question of checking whether you're currently in a desktop environment and take advantage of the additional functionality provided by the AIR runtime.
I see AIR as an 'enabling' technology rather than something new for people to learn -- HTML, Flash and Flex developers can leverage their existing skills and now deploy to the desktop.
In many ways the important news here is the concept of the web converging with the desktop, not what may or may not be included in an AIR 1.0 release, or even whether it is a solution coming from Adobe, Google or Microsoft.
We can only hope the various solutions play nice and can coexist peacefully. One thing I'm sure of is that this move is radically redefining the deployment and revision model for applications and redefining our idea of web 2.0 applications as we know it.