Now that I've your attention...
I own and have studied almost all the Flex 2 and ActionScript 3 books published. However, when I encounter a problem in my Flex application development I first search through the online documentation provided by Adobe. Almost always I find the answer to my problem in the documentation.
I've found the Flex and ActionScript documentation provided by Adobe to be well-written, with example code I can follow and learn from. It's nice to have an online version and a PDF I can download for those (rare) times I'm not connected to the net.
Here's a big "Thank You!" to all the people who wrote the Flex and ActionScript documentation and created the examples. I also appreciate the ability to link directly to a specific part of the documentation and to post (and read other's) comments about specific topics.
So sometimes, after I've found the answer to my problem in the Adobe documentation, I ask myself..."Did I really need to pay $35 for that new Flex book?"