Let's see
Various comic books/graphic novels
a big collection of sci-fi/fantasy novels, including most of Terry Pratchett's discworld series and the Hitchhiker's Guide
nearly every Star Wars Lego ever released (not in my room at the moment though)
an Arduino (microcontroller) plus additional hardware (LEDs, sensors, ...) if that counts
the (really big) Monty Python biography
DVDs... lots of DVDs
and I use old but fully functional PCs as shelf space
Furthermore I'm thinking about purchasing a replica of the sword of Omens from Thundercats, if I figure out the shipping restrictions. Damn this import laws!