Yep, I throw most of mine away. A classic smith or something is a different story, but a Glock 23? Nope, in the trash it goes.
While I certainly agree w/ the above, that classic Smith was not a classic Smith when purchased new. Look at the difference in prices now between "like new" and LNIB. I can't see a Glock 23 as ever being collectible, I don't want to take any chances, so I keep the box. I, however, do not have the collection that most of you do, so I don't run out of room for boxes.