Good Third-Party AS3 Editors

From the look of things, Flash’s built-in IDE is a little harder to work with than I’d hoped. I’ve heard plenty of people complaining about it, but I never gave it much thought. The auto-format post in the CS3 topic shook me up a bit, though. Maybe I should try out a third-party Actionscript editor and see if I like anything that’s out there.

I have a Mac, but I don’t think I should limit this thread to Mac software. Does anyone have any software they suggest, for either platform?