Fishing Tackle Boxes! I've purchased these Flambeau Storage Boxes from Canadian Tire, along with a soft tote to carry them in. They have their uses: great for taking beads to classes, I can carry a large assortment easily. It even has a place for fishing line (so handy to bead with), and a hole for pulling it through. Downside, the dividers, if they lift up, means your beads will get mixed up. Also, if you change your mind about one section, you have to use a narrow scoop, and really work to clear out the section. I have quite a few, and still use them to sort large quantities of larger beads (like when I purchase crystals wholesale). I've abandoned these as a way to store seed beads.
I haven't tried those screw together round plastic tackle boxes. The stacking idea doesn't appeal to me.
So, today's recap, in my studio there are (not in order of preference!):
Fishing Tackle Boxes
Vintage Glass Mason Jars
Round Aluminum Watchmakers Cases