I've started to collect those little tiny helmets that you can stop at the exits of grocery stores and get. I currently have: Chiefs Saints, Falcons Bengals, Browns Discuss.
I was debating buying the bigger yet smaller scale NFL helmets, but they run $26 a pop, and at 32 teams that's roughly 832 dollars...
I remember being obsessed with those little helmets as a kid. I would always want to go to the grocery store just to hit the machine by the exit. I even asked Santa for a bunch in my Christmas stocking.