Software you should learn if you want to code
Plain and simple, must projects at Github are using the following languages, data tells us that they are hot even though some of them are old. So I predict they'll still be hot the following year.
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Javascript
The browser allows you to run any software, and you can code it with Javascript. And you can code the server side software with Javascript too if you want. So go out and learn some Javascript and while you're at it, learn Node.js, jQuery and one of the cool Javscript frameworks out there like Backbone.js or Ember.js
PHP or Ruby
Yes, PHP is old, but it's still hot, specially with some of the cool frameworks out there. You can go with Ruby but you should learn one or the other. IMHO, I don't think the Ruby guys were happy when Twitter (probably the most famous project written in Ruby) moved to Scala. Facebook still uses PHP so that must mean something. One more thing about PHP, there's plenty of talent out there who code in PHP, plenty of documentation and a vibrant community. If you're gonna learn PHP try also learning a framework like Symfony
If you won't learn Ruby, I should probably tell you that you should learn at least a little bit because you'll be missing software like Capistrano.
Python
Python is cool, is a high level language but it's really powerful, you can write very complex software with it so learn Python.
Shell
You don't know GNU/Linux until you learn how to code your own scripts, and it's not that hard. Trust me, you can automatize many of the things you normally do when working with the console.
C or C++
Yeah, it's still used today, a lot. When performance is needed and you have time you must consider C for your projects, especially if they are complex and you must somehow interact with hardware.