FJR and TL bring up a good point — if you’re driving a Japanese car, don’t bother with SAE wrenches; anything American before about 1970 can skip the metrics. Theoretically, if you work on your car enough, you’ll learn which sizes you always use and which ones you can leave at home.

I just caught up in an out of nowhere torrential downpour. My rear window was covered in sludge and I couldn’t see any details from the rearview mirror. I pulled over and squeegeed it out of the way with the winter brush I didn’t take out of the trunk yet. An old towel or one “borrowed” from a hotel will work too.

I second the crescent wrench, but carry two in case of opposing fasteners.

On the flashlight side, if you use a AA powered light, get the new lithium batteries. Lithiums will last longer in storage than alkaline. There’s nothing about a broken car having a dead flashlight helps with…

http://www.youtube.com/watch?v=8avOiTUcD4Y

Years ago I found a wedge-shaped truck box that fit behind the seat of a single cab. I still use it in my Xterra with the shade bar pinning it to the back of the second seat. Works like a charm!

In my own kit, I carry all of the above, plus a compressor (her van has one built in), a tow strap, more types of tape, a bottle of dry-gas, a beefy first-aid kit (hers is separate), and a pile of bungie cords.

Latex or other type of disposable surgical gloves. much easier to throw on a pair before poking around the engine bay/flat tire than trying to scrub out the grime afterwards. easier than hand cleaners.
Flashlight, with extra (fresh) batteries
zipties
duct tape
wire hanger. the pant hangers with the paper tube are best. makes a quick roadside slimjim. Or use the wire to hold something together.
small pad of paper (steno note pad)
pen/pencil
cheapie disposable camera with flash (in case of accident, document the scene and CYA if it’s the other guy’s fault)

Hell, I’d call AAA before I’d figure out what to use a file or hacksaw for.

Then again, the most extreme repair I’ve ever done on my car was replace my headlight bulbs.

In addition to some of these tools, I’ve got a hammer (because it was a cheapie from home that I replaced with a better brand), two glow sticks, a gasoline siphon (it came in an all in one car tool kit), a mylar blanket (it came in the same kit), and some powdered graphite lube.

Zip ties - Plastic and metal
Leather gloves
Crescent wrench

1) Jumper cables

2) Small air compressor or pump

3) Tire repair kit. Green slime if you’d rather. Yeah, slime should never go into the tires because it’s a bitch to get off, but if you already used your spare and you need to fix a second tire so you can drive somewhere safe before you can get repaired, it’s better then nothing.

4) if you have a truck, I’d at least toss a tow strap in somewhere incase you need to try and help someone’s car out of a situation. Not like they take up too much space (Chains and ropes would take up more, but i can’t remember which of the three would be preferred)

4a) folding shovel if you plan on being in mud or sand at all to help try and dig your stuck wheels out.

5) Small flashlight (a 1~3 watt LED would be perfect I would think) or a large maglight (the 6 d-cell one works great as a club to hit things with)

Getting back to tools, a breaker bar or (possibly preferrably) a decent length of pipe that will fit over the lug nut wrench and ratchet. Especially with how a lot of the monkeys at the various shops around use the air ratchet wrong you might have some trouble loosening up the bolts when you need to get in at something. it may not be the right approach, but if i’m stuck on the highway trying to fix something so i can get on my way, I want that bolt loosened toot sweet.

For anyone who drives a Honda Only 8, 10, 12, 14, 15, 17 and 19mm sockets and wrenches are needed.

I know they are more supplies than tools but I dont feel comfortable without a jug of water/coolant and some oil and power steering fluid.

I would also include some Duct/Gaffer’s Tape and some good electrical tape.