Today the final version of the Flash Player 9 for Linux has been released - go get it!
I have actually enjoyed two beta releases prior to this final release and I have to say there were stable enough for me - despite the odd Firefox crash while watching several movies in a row and occasional video/audio synchronization issue that I didn't like. I'm already seeing the effects of audio/video synchronization issues that have been resolved in the final version and I really hope it proves to be more stable as well...
I find it especially pleasing that, probably for the first time in history, version number of Flash Player for Linux is higher than version number of Flash Player for any other platform - it used to be the other way round...