at present:
SML
C/C++
a little bit of Perl
when I first graduated in Engineering almost all my programming was in FORTRAN.
I have programmed in assembler (ARM, 6502, 8086), Prolog, Java, BASIC (BBC and others), Verilog.
I've learned/looked-at but not really programmed in ADA, Haskell, Python, Scala, F#, Ruby, Pascal, various others I've forgotten.
I think it is a good idea to get a little experience in samples of the main types of language. So a procedural language like C/C++ or Java or ADA or FORTRAN;
a hardware language such as Verilog or HDL, a functional language such as SML or Haskel or OCAML or F# and an assembler like ARM or MIPS or 8086, a scripting
language such as Perl.
Most engineers don't do any programming in functional languages (I only came to them late and because I'm a Computer Scientist now) but I think they do
provide a good mental discipline and will make you look at your programming in a very different way which might be useful even if you continue to use C/C++ etc.