I've got a bunch of Peli cases, each with different kits in, and one that's my every day gig box. It goes everywhere with me, and is constantly being thrown in and out of vans, kicked, stood on and abused. But I know that everything vital inside it is safe and secure.
I keep other cases stocked with microphones, tools, my SMAART kit, and have a bunch of smaller ones with little kits in.
Totally indispensable.