I agree with Todd Gardner that familiarity is probably the biggest factor determining the success of a programming language choice. So if you are much more familiar with one of those three languages than the other two (or whatever your other options are), I would recommend picking that one.
However, if you are equally unfamiliar with all of them, then I would second cloudhead's recommendation of Python. I believe it is the easiest of the three to learn and become productive in.
