I wanted to strike a balance between LED brightness and current, so I wired a few of them on breadboard, then I realized that I can use the breadboard bus to space them out as they would be in finished cube.  Of course, in the real cube each of the 64 LEDs will have their own current limiting resistor so brightness won't be affected by the number of LEDs that are lit.

The photo shows a glow around each LED.  In real life there is no such glow and the LEDs are not as "loud".  Just a serene peaceful sea of blue.  This is going to be awesome!