Python in a desktop environment

[David Cramer]

If you had an application that you were about to begin development on
which you wanted to be cross platform (at least Mac and Windows),
would you suggest using c++ and Python?

I'm asking because we were originally thinking about doing c# but
after attending PyCon this year I'm reconsidering. We are already
using Python for the website and I figure a c++ backend w/ a Python
GUI may work really well, and would be pretty easy to port.

Any opinions?