With the lights off, you can't tell what color it is. Heck, I have red t-mold on the right and blue on the left, but you can't tell all that much. I've got the Ms. Pac, DK, JP pin, and Asteroids for all my colored cabs. I think the all black MAME looks nice (not cheap, as it was suggested), and it gives me room for side art options.

Note: The green light in that pic has been replaced with blue and a MUCH stronger black light presence is now in the room. The colors really pop now.