If you are going for aesthetics, then you matching colors for all your boards might be the way to go. However, if they differ in tone, it will be very obvious and I promote using different, but complimentary colors.

On a technical aspect, green and yellow tend to be very distinct and allow you to spot traces better. So if you messed something up it is easier to bodge together a fix on a green or yellow board.

On a personal aspect, I am a sucker for red. I want red pcbs when I am not worried about time.

Yellow suits tube technology better (aesthetically speaking)

The one that matches the Arduino

Yellow, of course, but I prefer it with black silkscreen.