in reply to Which language would be most helpful?
I would go with C++, that is what our courses are at my university.
C++ is such a huge language that in my opinion, if you can learn C++ you can pretty much port your experience to any other language.
I was doing C++ ever before i got into perl or VB, and i have had no major problems..
Now i dont use COBOL so i really cant comment on that.