I love collecting but I don't want the stuff to take over my house, so I just keep my MOTU collection in my study. I have a really nice display shelf - five by five large and deep compartments - that covers one wall, but I still have more stuff than I can fit on there (I stand the cards up on plate stands). My solution is to rotate my collection. Most of the stuff in is packed away in boxes, and I swap things round every so often so that I don't have an overwhelming amount of stuff out at any one time. That way I get to really appreciate the pieces on display, and have the fun of 'rediscovering them' every time I take them out of storage.