I use this case from Platt which came with pre-cut foam. The foam is in a matrix of squares that you can remove to size whatever you need to fit. In my case, I store my Arduino, a small breadboard, USB cable, and few random components in small plastic bags (resistors, LEDs, etc.)
http://www.frys.com/product/4781479
(I'd have a picture of it, but I am traveling without it. I find this ironic since I bought the case for storage and for when I travel...)