My wife drew these up and forced the issue

; the clutter was keeping me from wanting to actually do anything. Despite what you may see here, it's usually pretty open and useful. We used a similar shelf type as djjsr above. Whole unit is 3/4" birch ply, 1/4" roundover edges, with 2-3 coats of clear poly.Tops and bottoms are rabbeted and glue-n-screwed, shelves are removable with 6" spacing. The extra cuts are thanks to a funked up router jig on the first run. There is a support bar across the back at mid-height and the center most shelves are glue/screwed for stiffness. The whole shebang is screwed to the studs through a board at the top. We built three cabinets, all 30" wide, 18" deep (I think); one full width shelves, one half width, one at about 1/3, 2/3. We cut and finished the doors, but never got to putting them on. I kinda like not having to swing out doors, but it would be nice to keep the dust off everything. They're spaced ~32" apart to fit all my other garbage (compressor, bandsaw, work bench breathing room) with a shelf screwed across the whole length for bulk storage (4th pic; motorcycle anyone?).
The last pic was a quick bang together using one sheet of 3/4 ply and 15 2x4s in a couple hours with as few cuts as possible. It's not attached to the wall, but really should be. Quick and dirty, how things usually get done around here.