Cobol, Perl, C and C++for serious stuff. For games probably Basic or (better) assembler since speed plays an important role, if not the most important role in most games. The problem with both is there is (as far as I know, correct me ASAP when I'm wrong) no standard for them.
For certain applications, like e.g. database you definitely need knowledge of SQL.
I forgot Java, because I know too little of it.