I was going to save this for my own thread, but I'll go ahead a prepost some pictures here for you.
I bought some shelves at HD, $76 each. They are 4 ft wide, 2 ft deep, and 6 ft tall. They hold 800 lbs per shelf. I bolted the shelves together and sunk a few screws into the wall just in case. The bottom shelves have 2x4s under them for additional support for the really heavy stuff. I left the bottom shelf out of one of them, and habe a transaxle and engine sitting on the floor.
I had some scrap 5/8" plywood that I made the vertical panels out of. Primed and painted them black. With washer on them, you can screw them on with 3/4" sheet metal screws. The horizontal pieces, not shown here but are just being put on now, are 3/4" sanded plywood, also primed and painted black. I bought one 2x4 piece for $15 and was able to make top and bottom headers for all four shelves.
End panles will be 1/2 plywood. Only need 2, so one sheet of 4x8 plywood ripped in half, at what, about $15? They will be primed and painted black as well.
The doors will be 3/4 inch hardwood plywood, stained a deep red, and mounted with hidden hinges. If you buy them in bulk at HD, they are something like $14 for 10 hinges, if I remember correctly. By the pair, they are like $6, I think.
Door pulls are something special. I'll save that for my own thread.