The midsize box is great for holding random bench gear.



As an added bonus, they all clear my truck bed cover:



Home Depot periodically sells the three box set (Wheeled base, middle, and upper) for $100. The smaller boxes and the crate run $29 a pop. They are not particularly square, and I'd call them 'water resistant' instead of water proof, but I think this system is absolutely awesome for the price.