The crackleback was invented by Ed Story of Feather-Craft back in the 1950's.
The original color was a light olive color.
Yellow of course has been very popular as well.

Dpenrod gives a lot of good advice about colors. The green flashabou body can work very well.
A white body has worked well for me at times. Try various colors and various hackle until you find what works best for your home water.