I store mine on acrylic sheets. You can get them pre-cut at Lowes or they'll cut a sheet down for you. Mine are 8 1/2 x 11. My stamps have the foam mounting (either from SU or I use EZ Mount for others). The image is on the mount and I spread a thin coating of Aileen's Tack It Over and Over on the mount because SU images don't stick to the block for me.
I stick the stamps on the acrylic sheets and put them in file folders. I have them arranged by type (Christmas, Floral, Flourish, Birthday, Sympathy/Thinking of You etc).
I put these folders in those bins with the slanted sides like: (http://i.walmartimages.com/i/p/00/02...03_300X300.jpg
) They are easy to go through to find the stamp I want. Sometimes a stamp will unstick from the sheet but it will stay in the folder or bin so I don't lose them.
I have a couple of blank sheets I use to stick stamps on when I am working because I may do several of one type of card and want to use the same stamps and don't always clean up after I am done (or I clean up when I can't find the top of my table haha). That way I don't lose the stamps and can easily put them back in their folders when I'm finished.