Right now, everybody and their mother are talking about Flash 8. I’ll just add a bit more echo to the choir and speak about I think are the coolest features about this new version.
3. Improved readability. With the new font rendering algorithm, Flash will finally get rid of the blurred mess of vector art you get when you try to use antialiased fonts. It’s a bit hard to judge how this has changed from examples of this feature online, and I’m not sure if there’s something changed on the exporting process that would require a real Flash 8 compilation for the features to be available, but all in all, I believe this will be great to work with in the future.
2. Bitmap caching. Won’t solve everything, but will still fix 98% of the cases where you need speed. No more progressive slowdown on stuff that just gets more complex even though everything’s frozen, yay.
1. The bitmap object. Seriously. With the new flash.Display.BitmapData class, you can manipulate images and all that. While this is cool – hey, you can recreate water applets that were already annoying 5 years ago and restart all the madness! – the good thing is that you can acquire bitmap information from movieclips – capturing them using the draw() method. In practical words, you can load images, save them to BitmapData objects, then reuse them as you need. One of the biggest grips I had with Flash until now is that you couldn’t load graphical assets and duplicate them, neither load them from other movies and attach them around. We finally can.
Honour mention: Blending modes. Something I have always wanted since what, Flash 3, but I didn’t believe they’d ever add it.