I didn't think of this before, as emergency-kit stuff is just always in my vehicles at all times, ready for use. A set of jumper cables is always a good idea, but I would advise getting some heavy-gauge 20' cables, if you have anything less. With the way many cars are these days, you never know when you will have the only car that can help you out be one that has the jump points on the opposite side of the engine bay in the next parking spot over. A 20' cable beats having to push the car out of a spot. Additionally, I would get a Li-ion jump-start battery pack. These things are great little devices, just make sure you get one that's big enough. I had one for a 4-cyl and one for a V-6. The 4-cyl one was so small that it couldn't even jump a 4-cyl car alone. You can plug them in to charge them and leave them in your trunk for 3 months without a recharge. FWIW, I always carry a roll of duct tape, a small spool of wire, and some rope. The rope can be used to tie things on/down. The wire can be used to wire things together or can serve as reinforcing on a coolant hose that blows or is about to blow. The tape is a suitable quick-fix for any non-solvent hoses/lines that need an air-tight, water-tight seal. I also always keep a 5-quart jug of oil and a gallon of coolant in the trunk. A 5-gallon gas can also isn't a terrible idea if you're going through someplace super rural. There are exits in Montana which have signs that say things like, "Last exit for 35 miles. Last service for 72 miles." 2 or 3 gallons jugs of spring water also come in handy.