I prefer open shelves over cabinets in the garage. The garage is an active place for me and opening cabinet doors adds extra steps to my tasks. I can understand if looks are more important for others.

All my shelving is made from 3/4-inch plywood with either framing or shelf brackets. Anything thinner will sag under the weight of my stuff. Shelves are 2' deep, unless they are overhead, then they are 18" deep with shelf brackets.

Workbenches are made from 2" x 12" boards framed underneath to a custom height (I'm tall).