http://sn.1w6.org/file/-20140601T172825-l3a8szj.html
@cmhobbs C at least, but depends where you want to work, just like in industry. For web, PHP, Ruby, and (some may disagree) Perl, plus the normal front-end things and frameworks. For systems, C, !cplusplus (less so in !fs). For applications, C, C++ (if in #kde / #qt), Vala (if in #gnome), Java, Python.