I don't really know what qualifies as "cool stuff" and whether I have any, but here are some things:
My autograph by Charles Martinet, the voice of Mario (if you're interested,
here's a picture of me with him. Yeah, I look stupid)
My Fallout 3 Collector's Edition
A pretty big book all about Spider-Man. Quite informative, should you happen to be a fan of the webhead.
And my binary watch. Bad picture quality. It was 8:29 pm when I took that picture.
@Nepsotic: I am SO jealous of your Doctor Who collection...