Programming for a mathematician?

I have started studying Haskell. I expect the type system and monads to be the most interesting things to learn (I know common lisp and have already seen many cool features). Though the days of general programming are long gone. I am interested in writing math apps though. Should I continue learning Haskell or should I start studying Mathematica (or some other alternative like matlab/maple) instead?

Like >>6-kun said, you really need to be more specific when you say math apps. Each of the big math languages are designed for specific problem domains (though they do include other general functions as well).

Mathematica, Maple - symbolic math with numerical solvers
MATLAB - matrix calculations
SAS - statistics