Python has recently become my default language for new projects. There are several reasons to use python.
Because it is very readable, and “can be seen as either a practical (better libraries) version of Scheme, or as a cleaned-up (no $@&% characters) version of Perl” (Norvig). Treating incorrect indentation as a syntax error is very helpful when working with people who would otherwise indent code at random.
Because it is good at a wide range of tasks, it is causing the “The homogenization of scientific computing . . . steadily eating other languages’ lunch”, and is “all a scientist needs”. In contrast, MATLAB feels extremely powerful within one domain (essentially anything involving a matrix), but extremely clunky outside it (particularly anything involving a string).
Because IPython notebooks are awesome for rapid prototyping, as well as communicating with others. But, if you’d prefer a GUI that looks a bit more like MATLAB, there’s also spyder.
Because there are many other reasons to “push for Python”.