I save the boxes, because it is fun to look at the boxes, and see the price tag on them. The hobby shops that are long out of business, and the prices that I wish still existed! The Bachmann, PCM, and BLI boxes are no-brainers, as they are good quality, and don't deserve to be thrown out. I always keep the MDC and Athearn BB boxes, just because I have the room to store them.
On a side note, I also keep the boxes to my Walthers buildings too. I take the front of the box, and frame them on the wall across from the layout. They look nice, and show the many structures on the layout as what they were meant to be built.
I wish I would have saved my boxes from my first buildings--ADM Concrete Grain Elevator and Walthers Meduca Cement. Anybody have them??...
Phil