We aren't partial to any one particular color, and will defer to the designers, and provide feedback. In addition to the mediums below, we are using the logo on our truck and trailer. We have yet to decide on our trailer background, but are considering using an abstract one similar to:
http://www.extremegametruck.com/ . Previously we were considering a white or light colored background with colors similar to the Mario Bros. (red, blue, green, yellow). Since we've yet to decide, we'd like the creativity of the designers to dictate which way we go.