Which programming language should I learn?
It depends at which stage in your (learning) career you are.
- Read Which language should I learn first? if you've never programmed before
- Read What to learn after the language? if you already know (most) of a language
- Read What are the strengths of each programming language? if you're trying to decide in which language you should write your next project, and you already have a robust foundation as described in the previous two links