I had the same problem in my garage after the 'race car' came and lived with me for a year. The house I moved into had 1 quad door over/under wall particle board cabinet up in the storage area, I added 2 racks of Whalen shelves for $60/each from Costco. When I filled the shelves and cabinets with car parts, oil, trans fluid, brake cleaner, spray paints, housing paints, moving blankets, car covers, tailgating equipment, etc. I went and did this a couple weekends ago,
before (notice the shelves and cabinet on the far back wall, all filled up):
after (2 sets of those cheap white particle board 3 door cabinets, CL $120 for both after painting, reinforcement and mounting hardware ~ they run around that price each unassembled from HD):
So my advice is if you want storage or cabinets go with CL and be creative. Over on Garage Journal there are a couple of amazing threads regarding re-purposing everything from old 2nd hand office cabinets to old kitchen cabinets people left by the side of the road: What do your storage cabinets look like? and What's your workbench look like?
Enjoy!