My computer with all my photos and homework and diaries on it.
My really nice camera.
My really big TV.
I guess I'd lose my entire Game Boy collection, NES game collection, DVD collection, and record collection. That would suck. But I'd be able to sell the big TV, hopefully for enough money to buy a small TV and books for school. And I'd get to take photos of my house burning down, which would look pretty cool.