[r3570r3]

Well, it totally depends on what you want to achieve from learning any programming language.

IMHO, these are the ones you should know and they cover most of the scenario.

  1. A desktop programming language, compiled and robust like C.
  2. A regex wizard like Perl.
  3. A strong web based scripting language like Javascript.
  4. An interpreted and readable language like Python.

If you like to fire up your own codes from time to time, these are the ones you should know. Though, if you are into specific development fields, this list does not matter. You have to learn something specific in that case.