I have a spot in the corner of the garage for the brew stand. Kettles are stored in place. I have shelving next to it with the mash tun and two plastic storage boxes full of hoses, worth chiller, and various gear. In my closet, in the house, I have another storage box with things necessary to make starters (flask, stir plate, extra specialty grain) and deal with kegging, cleaning. Iodophor and oxyclean are under the sink since that's where they get used. I also have a small toolbox that contains all of the little stuff, stir bars, grommets, thermometers, gaskets, servomyces, lactic, etc, etc.
I don't do bulk grain storage, but may some day. I need to relocate my grain mill and motor/table over by the stand since my old summit kegerator is going to be positioned next to my other storage fridge on that side of the garage.