I have my own home theater set up, and in the closet with the movies and games I keep all of the boxes from electronics purchases.
Boxes:
iPhone 2G: 8GB and 16GB
iPhone 3G: White 16GB
iPhone 3GS: Black 32GB
(June 24th) iPhone 4: Black 32GB
2x MacBook Air (1st gen)
3x MacBook Aluminum
MacBook Polycarbonate
MacBook Pro 13"
MacBook Pro 15" i5
iPad 32GB WiFi
Apple iPad Case
Mac Mini
Airport Extreme
In-Ear Headphones
XBOX 360, PS3, DS Lite, DSi, PSP, etc...
Camera gear (Canon EOS, lenses, etc...)
Random other stuff.
Basically, I need 10 shelves for boxes alone. But at some point it had become a cool way to decorate a small and personal home theater.