big toolbox with assortment of wrenches, both SAE and metric, combo and geared. vise grips, t-handles, screwdrivers, propane torch, axle grease, and a few sockets.
medium toolbox with emergency poncho, two tow straps (one with hooks), emergency fire starter, brake clean, PB blaster, other random stuff
small toolbox with assortment of electrical connectors, butane, butane torch/soldering iron, heat shrink, solder, wire strippers/cutters/crimpers, extra wire
3 fishing poles (2 spinning, one casting), tackle box, casting net (never know when you're gonna get a chance to go fishin!)
work-on-cars shirt, mechanic's gloves, 4-way, hydraulic jack, spare tire, 2 tie-downs, bottle of coolant, fireworks

, rod to hold up liftgate, eh.....i THINK that's about it!
I learned shortly into this XJ foray never to leave your tools at home. It's a recipe for disaster! So far, in the 6 months I've had this XJ, I've changed an alternator, u-joint, 3 tires, upper radiator hose, and 3 starter buttons, on the side of the road. I tend to drive a lot so it would be stupid not to take some tools with me. I also work on friends' cars and bikes on the side for some extra cash, so this way i don't have to load them up every time.