Why Python over Ruby?
plaes: Python has IMHO better support for GUI toolkits - Tk support in main library,  PyGTK+, PyQt. And two more words about library - import antigravity :).And strong company backing:
Google has have hired some of the core Python developers, and some of its infrastructure is written in it...
Flumotion with its streaming media (although codec stuff is mostly gstreamer, but most of the networking stuff is in Python)And the final straw - Python just seems to be a bit more beginner friendly...