I have a rolling Pelican hard case for lighting gear, it has a Quantum QFlash, Sunpak 555, batteries, stands and modifiers in it.
My cameras are in a soft sided Pelican rolling case. I usually stow both cases behind the DJ table if there is room, or in my car.
At the wedding, I wear a Lowepro Street & Field Belt, 5D2 w/ 70-200 & 430EX on a Spyder Holster, 5D3 with 35L & 580EX on a strap. On the belt, Lens Exchanger bag with 17-40L, another pouch with 50mm f1.4, and another bag with extra batteries.
My assistant carries 5D classic, and a camera bag with 35mm f2, 50mm f1.8, 85mm f1.8, a couple flashes, more extra batteries, and the Qflash for portraits.