Since you're a fan of eeyore, I'd definitely go for an eeyore stuffed animal, and maybe a shirt or sweatshirt. I also agree with picking up a 50th anniversary souveneir.......it's once in a lifetime chance! Let's see, what else...........oh yeah, mickey ears are a must. Especially the golden ones.
My favorite souveneir that I've gotten was a glass slipper. I still need to get it personalized with my name though.
All in all, buy what you want! It's your trip, and have a blast!