Ooh medals. Good idea, but I think there should be medals for attendance, post count etc that anyone can get, and unique medals which are awarded on a quarter-yearly basis, with each award winner being presented with a unique medal. Each subsequent awards ceremony shall have similar awards, but different medal graphics.
Any medals worn, could be put underneath the user's name, or thereabouts, for all to see, and there should be a link somewhere to a medal chart, where the name and nature of each medal is shown, so you know what each medal represents.