I carry a four-way tire iron, battery jumper / air compressor / portable power supply, Titan exhaust jack (thank you Marlin), LED flashlight and spare batteries, power inverter, WD-40, Fix-a-Flat, First Aid kit, tow strap, small screw driver with bit kit, ratchet with metric set, duct tape, quart of oil, snow scraper / brush (winter only), fold-up camping shovel (useful if you ever have to dig yourself off the beach), flares, bottle opener / corkscrew, razor blade, and fire extinguisher.

All that fits in the Tone box I got from Grant Eaton, plus the dog can ride on top of the box.