- C - Python - JavaScript

This is, of course, only based off of what I know so far and what I would find most useful. I could probably trade JS for a SQL, though, if I was thinking purely in terms of work that I'm into now. I don't use C at all, except to look at Python bindings occasionally...but all the concepts I've learned from learning C are vital, even when working with high-level languages. Plus, it'd be nice to switch to iOS development at some point.