Metal, hard plastic, or tool bags?

[outfield]

I carry a canvas bag of tools in the Land Rover all the time, metric wrenches of course, sockets both SAE and metric, screwdrivers, hammer, vice-grips and a couple specialty tools just for the Rover. It's secured with a nylon strap just behind the passenger seat. I like it because it does not rattle.
In the pickup bed tool box I have a plastic storage box with a complete socket set in it, and a craftsman soft case with the remaining tools in it, wrenches, screwdrivers, hammer etc.
I'm leaning toward the soft cases more now because they don't slide around and the tools don't rattle.