On a wall in the basement.
In my basement, I have a built-in cabinet along one wall. The shelf on top is the collection site for the Macs themselves (with a few scattered around the house as Internet terminals, and a couple on the basement desk to play with at any given time.) Two of the cabinets are dedicated to holding all the paraphenalia, such as disks, external drives, cards, keyboards, mice, etc.
My
.Mac site has pictures of the collection from a couple years ago (the notebooks alone have more than doubled in number.) I just recently took more pictures, I'll put them up on my new iWeb-based site tomorrow.
As for the 'prized piece'? Either the Backlit Portable (which was functional until a couple months ago. I think the battery finally gave up,) or the Duo 2300c with all original packaging, whose battery ALSO gave up the ghost a little while ago. I also have a Newton 120, but it died too recently. (One day it wouldn't power up, no matter what I tried. It was working fine the day before.)
I think I'll be offering up my 'dead' computers, plus the duplicates in the Marketplace soon. (3 truly dead ones, 6 or 7 more that are really bad in one way or another, plus a few duplicates.) The dead ones will go for just the cost of shipping (or best offer, if more than one person wants it,) the 'bad' ones for $5-$10 plus shipping, and the duplicates, who knows...