wxPython has long been my favorite toolkit for developing cross-platform interfaces that actually work. It’s not perfect, but it’s a hell of a lot closer than other alternatives I’ve tried.
I’m using wxPython in ccTag for Creative Commons. I just downloaded the new version, 22.214.171.124, and it’s most notable new feature is not all of the Mac OS X improvements (although those are cool and needed), but rather the improved documentation. For a long time the best documentation for wxPython has been the documentation for wxWidgets, it’s C++ backend. So you would look at the C++ documentation, translate the methods in your head, and hope you got the translation right.
Now, thanks to EpyDoc and lots of work by Robin, we have the beginnings of real wxPython documentation. It’s amazing how much more productive I feel using them than the C++ docs, which I had sort of resigned myself too. Great work, Robin.