About 90% of the time I keep the boxes, so I voted yes. ****, I have a box full of my PC game boxes, and a FedEx box with all my manuals/books on my games. I also use a box where I store a hard drives, tools, and other PC parts.
When I ordered the DVD collector's edition of HL2, UPS stored it in a huge box (almost 12x as big as the actual game box) and stored the rest with sealed plastic bags of air for protection. I am currently using that box for my magazines (as I keep those too, still have my 1998 PC Gamer mag giving Half-Life game of the year)