At work (I'm a physics/mathematics guy developing quantum optical simulations):
Fortran 2003/2008
C++
LaTeX
Sage
Mathematica
Haskell (My initial experiments look promising; ghc+llvm has consistently beaten gcc and gfortran when doing RK4 integration of complicated functions. I'm currently testing array performance with REPA.)
Emacs
Dislin (Looking for a replacement, since it's a real pain
to use)
Charm++ (Looks promising, but also seems hard to use.)
Fortran 2003/2008
C++
LaTeX
Sage
Mathematica
Haskell (My initial experiments look promising; ghc+llvm has consistently beaten gcc and gfortran when doing RK4 integration of complicated functions. I'm currently testing array performance with REPA.)
Emacs
Dislin (Looking for a replacement, since it's a real pain to use)
Charm++ (Looks promising, but also seems hard to use.)
MPI
At home: Haskell