We have several steel wire shelves, on which we keep robots and totes full of wheels and other large pieces on the lower shelves, and blue stacking bins about 2 feet deep on the higher shelves. Most of our nuts and bolts are in the briefcase-shaped boxes with removable rectangular bins. Electronics is mostly in plastic units with pull-out shelves. The "briefcase" style boxes (similar to what Hitchhiker_42 linked for electronics, but ours are larger) are definitely easier to take to the pits because they cannot spill, but are a bit less convenient in the shop.
Most hand tools are in a vertical tool cabinet, but we're looking at buying a lower one that will double as workbench space in the pit, and be easier to strap in to the trailer. Most of our power tools are on a rubbermaid two-tier cart, because we usually take them outside to use them.
We have two
fixed shelves, and two rolling shelves similar to the ones Sam Perkowsky linked to. Note that those rolling shelves are OK for getting across a tile floor, but do not stand up to rolling into a trailer or across a parking lot (especially loaded); we had to take the wheels off of one permanently at Red Stick Rumble last weekend. The fixed shelves should have a shelf within a few inches of the floor, or the legs will have a tendency to buckle when lateral forces happen (and let's face it, they always do).
The most important thing (and we're not there yet) is to have a place for everything. When you add something new to the inventory, the question you should ask is "Where would I start looking for this thing?" That's where it should go.
Another thing we're going to try this year is to have several "oddball part bins" for people to put things when they don't know or can't be bothered to put them where they belong. Then, the job of fixing the inventory can (hopefully) become one of "put the oddball parts away" rather than "search everything for part's that are in the wrong place, then put those parts where they go".