I have two particularly nifty rare items I can think of off the top of my head. Carl Gustav Jung's glasses you always see him pictured in when he was in his later years- my great grandmother was Alma Jung, and we found them in her basement along with some of his books (sadly they were damaged in a flood) and some other random items.
I also have a screen-used "Grady's Inn" matchbook from Resident Evil Apocalypse, and one of the newspapers on screen from the end of the first movie (it's pretty neat, all the different newspapers shown in that scene were actually the same, with each page just being a different front page).
I have some fairly unique firearms too, but that tends to be one of those can-of-worms issues, so I'll leave it at that.
Edit: Oh yeah! I have a pretty neat fragment from the Berlin Wall with a bit of graffiti too, with a picture of it's source.