personally I have no preference on colour - as long as it shows up on a black background. Silver/gunmetal grey is normally pretty effective on pretty much everything.
I was going to have one for the car going to Le-Mans, and a couple for my Kart - so i think the website would be the best idea in terms of design.
I personally believe that cut vinyl looks most effective.
T-shirts and probably a couple of Mugs please Mate, along with the stickers

ahhhh - we're already ready for 2005!!