I think I have reached quite an advanced level regarding Flash and Actionscript 2 and 3, and now I'm thinking on taking a further step: either Flex or AIR.

I know they focus on different matters. Flex is still related to the web and browsers, but more programming-oriented than Flash. AIR focuses on desktop applications which require some Internet connection.

Both things look appealing to me, but I'm not sure how much of one of them is recommended to previosuly know before facing the other. In case that before facing AIR it would be highly recommended to familiarize myself with Flex, I would start with Flex, or just the opposite.

What do you think?