I'm an astrophysics/CS student, and IDL has been on life support at my university for the last 3 years. Everything is either done through Fortran 90 or C/C++ for simulations code, and the data processing is done through Python with some combination of GNUplot/matplotlib/yt, or maybe R.
Oh good God how could I forget about Fortran and GNUplot. F90 though? Luxury. All your code should be in F77 :P . I've worked on a few image reduction pipelines which were all in C++.
