For years I have used a Contico X-treme Tuff Box. It's strong, it's inexpensive, it has a key lock, and it holds a ton of gear.
It's perfect for when I'm going out with just the Tacoma (no trailer). My wife and I call it 'The Campsite in a Box'. It literally holds our entire campsite minus the food. In that box, we can fit our tent, our grill, cook set, therm-a-rests, sleeping bags, chairs, table, tripod, lantern, propane tanks, electric fan, camp tools, etc., etc.
The only bad thing is that IT IS HEAVY. You really need 2 fairly strong people to lift it when loaded. For the trailer, I've found this box to be too big and cumbersome for practical use. When in the trailer, it's difficult to find and reach what you need, and it's twice as hard to get in and out of the trailer. For the trailer, I've started using several smaller Action Packer boxes, and Pelican cases.