We are all huge fans, or we wouldn't be here. (My apartment basically looks like a Ravenclaw common room.) So, what sort of stuff do you have that you want to share? Where did you get it? What do you like the best? Do any of your (non fangeek) friends support your habit?
I think my favorite thing is a stack of parchment letters addressed to me at the Ravenclaw table in the Great Hall, tied with twine. The top letter lifts to reveal a little trinket box. I love it!
And Whimsic Alley is a gimme. :)