Remember there are steps you can take against getting certain things greifed. [I will post pics of these later]
Protecting Chests with signs is a simple one.
You can also protect enchanting tables, spawners, doors, furnaces.
Some of you have been in my shop where my enchanting table is. notice the sign. This makes your table unable to be stolen as well as useable to anyone.
Spawners are slightly different, some may have been lucky to have seen my two natural spawners i found about 20 blocks apart in the nether. Place a gate under the spawner. then on the gate place a sign by place it infront of it and protecting it just like a door. This protects the block under and on top of the gate thus protecting the spawner.
Doors are pretty self explanatory as well. place a sign add the players DONE. /lockette can be used on these signs just like any other protected sign.
Furnaces also are just like chests and doors. /lockette can be used here as well.
Using these kind of tricks you can protect your valuable items. Also keep in mind that if you wanted to protect say bookshelves or something similar you can just use the trick to protect spawners.