This is a very simple combo that yields a very special effect!
For the base coat, a dark polish looks the best for this effect. I used this pretty navy color called Up All Night by China Glaze. The flash makes it look a little brighter than it looks in person.
The top coat used is Snow Flakes by Color Club. This is basically an easier to find and cheaper version of Shine of the Times by Essie. It looks exactly the same to me :). I love it! Here's a couple more pics with different lighting.