[IKE]

When it comes to sponsorship recognition (an many other aspects of FRC), quality trumps creativity...

I personally like receiving quarterly news letters and a thank you card. Ideally the thankyou card should like like some effort was put into making it special for your team, and signed by many (if not all) team members. Plaques are nice, but they become difficult to find room for. If you are going to do a plaque, a neat trick would be to give the sponsor a plaque with extra room for extra sponsorship year badges. Then you would be sending a new plate each year (along with a letter, and thankyou card).