I perefer to build my own shelving out of wood. for my standard vans I built them from "shop birch" - my cabinetmaker friends term for 3/4" birch plywood. Costs about $45.00 for a 4x8 sheet, and I used 3 sheets. Along with a 1/4" sheet for the backs, under $200 in material. Everything is dado'd, glued, and screwed.
What I like is that everything is custom sized to how I like to store things, and also super quiet. One one van I actually removed the factory steel bins to install my wooden ones. I used the van for over a year and couldn't take it any more. Shelves were bigger than I like, and noisy as heck.
On my box truck, I built shelving out of 2x4's and regular plywood. Joints are half-lap, glued and screwed. Worked great. Other racks are built out of punched angle iron that I buy from a garage door supplier. They come 10' long with holes every 1". I just bolted them together for some larger shelving and ladder racks.
I'll try to get ambitious and post some pic's on "pimp my ride."