For cross-platform development, wxpython is great. It's a nice library and I've used it to make apps which run well on Windows, Mac, and Linux. I've used pyQT

For cross-platform development, wxpython is great. It's a nice library and I've used it to make apps which run well on Windows, Mac, and Linux. I've used pyQT for QT and KDE applications and I enjoy it very much. It's nice to be able to use QT Designer to quickly build windows and application panels and then use pyuic to generate the python code.