I use those plastic utility cubes you get from Big W to keep boards, plastics and other bits in.

For storage of playfields, I put together a Dexion shelving unit. The great thing about these is you can usually get them cheap thru the auctions or at secondhand office furniture places and you can adjust the shelf heights to whatever you need, and they are strong.

For backglass storage I made a special storage box with partitions. It holds about 10 backglasses and I keep it in our walk in robe, so that temperature is not too hot or cold and its fairly dark with no moisture or damp.

The box itself was cheap to make, and I will whack up some pictures later on what it looks like in case othres want to make one.