I wish I had not bought all those arduino flavours and just sticked to the Teensy.
The Teensy range is phenomenal (especially the 3.2): Here's the link to the PJRC Store
You can use C if you want but there is also an Arduino linker which allows you to program in the Arduino environment; Best of both worlds I guess. The teensy can be connected to the computer as serial, HID (mouse keyboard), midi, RAW and it also has 'hats' like this audio/SD-card one: http://pjrc.com/store/teensy3_audio.html
With an online drag'n drop Audio Editor which generates arduino code I had my distortion pedal ready in no time:
Volca Sample through DIY Teensy Distortion