Depends on the field -- I think Matlab is still a little more popular, especially among engineers, but SciPy (or just plain NumPy) is good for biologists. Ther

Depends on the field -- I think Matlab is still a little more popular, especially among engineers, but SciPy (or just plain NumPy) is good for biologists. There's also a need for glue code and other non-numerical scripting. For example, PyMol is a pretty popular program for molecule visualization, and as you can guess, Python is its scripting language.