I don't think anything I have is really all that rare, and if it is, not rare in the sense that it's worth much.
I DO have one of the limited edition (either 15000 or 1500 copies, I can't remember right now xP) brand new eyes box sets, because I love Paramore that freakin' much.
The amount of Disney movies I have on VHS will probably be worth a lot at some point in time.
I have a relatively old guitar, but little to no guitar knowledge, but I've been told they don't make them like that anymore.
My dresser is probably the most valuable thing I own (antique), but my futon cost me about $500 and is a damn nice futon (half a K is a lot for someone with no job who has to pay for uni) and I'm fairly certain that if I added up and sold all the books I have for their original price I'd have a hefty amount of cash.