At my space I made sure to build the walls with 1/2" plywood because at the previous space I rented I had to hang from picture moulding which is a huge pain and the miles of wires going up to the ceiling are not attractive. If someone opens a door or turns on ceiling fans the art moves around slightly making it even worse. I lived with picture moulding for several years at a rented space and changing shows was always a headache. Now it's great...lay out the show and hang anything anywhere. No need for studs with 1/2 ply even for heavy sculptural works.
You can cover the 1/2" ply with sheetrock, museum-style" but the ply looks really nice painted.
If you're renting or have old brick or plaster walls you're stuck with the picture moulding.
BTW, if you're stuck with the picture moulding, hanging from wires is probably the best method. I've seen other things that involve rods or rails and they are really ugly and distracting, even worse than the wires. Good luck.
