Built in wood cabinets...huge, from ceiling to about 3 feet from the floor, clear across the back.

4' wide, 2' deep, 8' tall shelves. They look like "gorilla shelves' you can get a big box store, but are bigger and stronger. Uprights are 1 piece, not 2 pieces. Picked them up from an office that closed. Look for used shelving from stores that are closing, or look for a used warehousing store near you for stuff that should be alot heavier-duty than stuff at big box stores.
If I ever get a 30x40 garage built, I'll probably be getting some used full blown pallet racks.

Costco sells a terrific, free-standing shelving unit made of heavy-duty, chromed wire shelves that fit over four corner posts. The shelves are adjustable and the whole thing sells for about $80. For that money you can assemble a unit that is 6' high, 4' wide, and 18" deep, with 6 shelves; or you can have two units that are 3' high. It's incredibly well-built (must weigh 100 pounds), and each shelf is supposed to be able to hold 600 pounds. You could jump up and down on this thing and I doubt that it would budge. I've got 5 of them in my garage and shop and they've been perfect. Because of the open wire design, you don't get dust buildup on them, either. The ones I purchased are available in the Costco warehouse, but they sell a 4-shelf unit that is otherwise identical for a little bit less online. And they both come with heavy duty casters if you want to be able to move it.

Here is a link that might be useful: Costco shelves

We were given two file cabinets, one a four (wide) drawer file cabinet and I was going to put it on Freecycle till it occured to me to use it to store tools and screws in the woodshop. Duh!

We use all sorts of stuff, including steel tool cabinets (for small parts and tools best organized in drawers), slatwall (to hang garden tools, ladders, etc.), old kitchen cabinets (for insecticide etc.), and open wooden shelving. We also use tightly covered cans or barrels for bulk materials (cement, garden lime, seed).

I like to organize the garage into areas focused on specific tasks (gardening, woodworking, etc.) This tends to require more than one kind of storage device for each task . A good, versatile task area can be set up with a wall of of slatwall panels behind a chest of drawers.

I like the "Gladiator" slatwall (although we also have the StoreWall product)
and roll-away chests. The large Gladiator roll-aways, equipped with maple tops, can be rolled out together to make a nice temporary work surface for finishing a door or cutting plywood (all the while keeping your tools in drawers below your job.)

I use the ceiling storage racks (I have 10' ceilings)

I got mine through Amazon.com - Target also carries them

http://www.target.com/gp/detail.html/sr=2-3/qid=1138816334/ref=sr_2_3/601-8238044-5972946?%5Fencoding=UTF8&asin=B0002IGHKM

Anything my husband can find. It's a 3 car garage and he already has it filled, luckily 2 cars and a riding mower fit, at the last house the garage was 24x28, almost a 3 car size and we couldn't get any cars in. This time he has shelves, old dressers, tables, plastic containers, and finally a place for everything, neat and clean. Lynn

We (that 'we' meaning my husband, that is...) just finished building two overhead storage racks, each 4x6 and with about a two feet drop-down. We attached metal bars to the studs, framed them up, and made the base of the racks with 2x4s. Best thing we've ever done. We don't have a basement or an attic, but now we can finally stash away all the plywood for covering the windows during hurricanes and all the other extra materials and boxes we had lying around in our one-stall garage. Wow-- we can even fit a car in there now-- what a great thing!

Built in cabinets on one side. I had it done with overhead cabinets with a countertop and base cabinets. There are under cabinet lights. On the other side is a built in
work table with shelves over it. There is a narrow cabinet
next to that to put things like cleaning supplies, oil etc.
Then there is a cabinet for brooms, mops, vacuum cleaners.
Next is floor to ceiling shelves with clear plastic boxes
that hold the other miscellaneous things that get piled into the garage.

I wanted it fixed so that if it were to rain out a party,
we could set up the food on the counter top,put tables in the garage and bring the party indoors. There is a summer kitchen off the garage and a covered deck beyond that.

A lot depends on what all you need to store. People who just store a few garden things and some other misc odds and ends don't need much. If you are an avid do-it-yourself type, then you need to think through it more.

One thing I have that I built from 3/4" plywood is a storage cabinet on heavy duty caster wheels. It is about 5ft high, 40" wide, 24" deep. Inside it has simple 1/2" plywood shelving at various intervals and a plywood door on the front. The doors have hangers on them for levels etc. The shelves sit back a bit from the door to accomodate hanging items. Other things that get stored there: tape, small tools, caulking tubes, boxes of screws/nails, power drills, etc. It keeps everything dust free and I can roll it around anywhere I need to move it.

Our old kitchen cabinets, that is the ones we replaced (2004 went from 30 to 36 cooktop/venthood - long story). We have Cardell modular cabinets, not "site-built" and are able to buy off the shelf. They look pretty good in the garage. Just replaced an oven cabinet in January 2006 so still sorting out what/where to store.

I am using two Hyloft racks mounted from the ceiling for bulkier items...and also using rubbermaid canisters to contain the smaller items.

I am also using the Hyloft brand shelves. They seem to be better constructed than the rubbermaid brand...and they are deeper (15" vs 12" deep) and you get two 45" length racks with each package. I have two boxes (4 racks) running the side of my garage behind the rollup garage door tracks.

I have three Gorilla racks which I bought from Costco with more rubbermaid tubs.

I also have three closet door storage units...which can conceal items.

Now...the best thing I ever did though was to paint the garage in a semi-gloss paint finish. That makes it cleaner looking and polished.

not much. when i built this garage its 26x26 10 ft ceiling, with storage above, and a pull down starecase. i had visions of building a hot rod, and this was the shop i always wanted 220, cable t.v. drywalled, trane furnace, but you get older interests change, etc, etc, i sold off most my tools and havent used it for anything, except storing 2 bikes and a lawnmower. anyone want to buy a fantastic garage, with a nice house close to it. haha

so far, I have a loft above the office area in my garage, it is 15X60 and 15X25 (L shaped) then in the car work area, I have a 25' long bench 48 tall and deep with one shelf below built out of 2x4's and plywood. several toolboxes roll around model, bench top and two or three portables. my wall currently has nails all over it and lots of items hanging from them. I have a magazine article that shows how to make modular shelves/hooks/etc with plywood/router and 1x1 angle aluminum. it is in the works for me. I have several shelves on walls, I have a 24x24x40 steel bin unit for misc bolts parts etc. it is sitting ontop of three steel shelf units, and they are sitting on top of a 30x30x48 Locking steel tool truck vault laying on it's side. (nothing in it at the moment, who can bend down there all the time, not to mention all the stuff on the floor in front of the door) hmm. I also have a 90 astro van up on jackstands stacked to the roof with computer monitors/printers etc.
very nice size garage, but could definately be better organized!
John

Well like ohmmm said, depending what you are storing. I like to utilize the unused space up above the garage door rails. I drill holes through the rail and attach a 2x2 and another one to the wall across from it then cut a piece of plywood to fit and almost instant shelves.