I have become quite fond of the Faust programming language, it’s a functional programming language that lets you quickly design audio processing and synthesis algorithms. What makes it interesting as a programming language is that signals are treated as discrete functions of time, so when you write a function it becomes second-order function over the signal. Plus it compiles to super-efficient C++ code with support for CoreAudio, Qt, GTK, VST, and Audio Units!
Since it is so easy to develop for I have been using Vim to write all of my code, but the syntax highlighting file included in the Faust repository was incomplete and had a few bugs. I extended the original file into a plugin with support for Pathogen and Vundle, MathDoc highlighting, and a few other improvements. Check out the repository on GitHub.