[EricRobodox]

I dont think it would be as safe, but would definetly look cool:
Lasers

I know they have Green and Red, but if there could be some cool way of shinning a light upward from the robot and have it visible, I think that would look awesome. (If there are other colored lasers, or lights [blue and red] , that shine a beam of light visible through the medium of the atmosphere)
Safety though would take another route probably, because of blindness that lasers can cause. Still think it would be a cool idea.