I use these Euro bin shelves for devices, trims, & mud rings. It's 2' deep x 4' wide and tall. Not the exact size but you get the idea: http://www.quantumstorage.com/flat_shelving_euro_drawer_system.htm
I seen them in a few catologs including Granger. They work great but I had to make a door to keep them from opening.
For tools I dont use every day I have a Craftsman bottom tool box. Pay extra for the rollor bearing drawers that dont open unless you lift the handle. It is nice fot protecting the expensive things from the hammers and drill bits. Also it locks.
Some drill / tool boxes are in a steel cabnet with doors and a few shelves.
For some items I bought plastic bins then made shelves to hold the bins. These bins I have fittings that I don't use every day but it is nice to reach in and grab one or take the whole bin full to the work area.
I made a wooden box with # 10 wire handles that holds 6-10 factory boxes of common 1/2" and 3/4" fittings. Those fitting boxes have emptied out on me one too many times while transporting, that's why I like my box.
Everything elce is made out of plywood 2x2 & 2x4's. Wood keeps the raddels down but can add some weight. Wood is easy to work with unless you try to use too small of pieces. For small light duty shelves it is put together with glue and a trim nail gun. The side walls are 3/8 with foam insulation behind to keep the walls from sweating and warmer inside. Some 3/4 is used for holding the pipe racks. 2' PVC tubs are held upright with 1 holes to hold the benders.
Bigger plastic bins are used for bulky items like nipples.
One bin is for the special ordered items waiting to be installed.
2 ladders slide in their own place while the smaller ones are straped in.
Everything cairred should have it's own place. More used items should be easier reached. Similar items should be grouped together.
Building custom shelves took us a lot of time and was an ongoing project. I do fell we have a better setup then the stock steel units.