I didn't know, until I downloaded Tour De Flex, just how badass this technology was.
Browsing through the sample demos, I realized you could really build a regular desktop application using these technologies. I mean, I've hammered-out plenty of C# applications that could have easily been Flex + Adobe AIR applications if they had been around back then.
And the install badges for AIR applications? It is, literally, out of this world. I haven't seen an install system look and feel so fluid since 3-4 years ago when I was looking at mockups of web-based Linux package installers (Autopackage?).
Still, all in all, it looks like a pretty solid set of technologies, and the development process is fairly similar to web design / programming. Could be an extremely valuable asset to pick up in the future.