Always love organizing ideas. Here are some of mine for you.
For Clear stamps, Sizzix dies and background stamps I use a vertical spinning DVD storage tower from Sears.
22 unmounted stamp cases or
19 bigz dies, or
13 wood mounted background stamps (taken out of the case & stood on narrow end like a book)
The shelves are adjustable so you can adapt it to your needs, I also store 6x6 DSP on these shelves. This is a great solution for a small space & cost $130.
For wood mounted stamp sets, I have bookshelves from Ikea with some extra shelves in them. I store the stamps in their case on the side. Shelves are adjusted so they just fit the width of each case. This way, you pull out one set & the rest stay in place. I have about 22 sets on each shelf. I organize mine by case size then they are indexed. I use my "inventory catalog" that I created for each stamp set I own so I can go right to it. Makes it easy to keep sets organized.