Well, lets see here…Change of clothes (tropical). Fleece zippered blanket. I've always got a bunch of flashlights, knives, and tools in my vehicles. Mylar sleeping bag, TP, duct tape, 1 ltr water (I'd drink it, plastic chems and all, if I had too…), some energy bars and more eats, personal hygiene kit, some spare prescription pills, extra reading glasses, extremely basic first aid stuff, water purifier straw, bunch of zip ties and para cord, small "office" (pens, paper, rubber bands), indelible sharpie pen for writing notes on the windshield, couple large garbage bags, fire starter and fuel balls, small book (Sailing Alone Around the World- Slocum), moist wipes, all in a nylon bag with a strap that could be grabbed-and-gone in a moment. Wow, no cockroaches! Surprise!
Living on a small island, my usual area of roaming is usually well within a one day hike from work to home. So I probably should concentrate on beefing-up the first aid department and tossing in a fire extinguisher. I did have occasion to use the bag last year. We had a tsunami warning that had me at work (4' above sea level) preparing, at 0300 hrs when they closed the roads. I had something to eat and a nice blanky to cuddle in till the threat subsided. That's the nice thing about a car, it's pretty easy- unless you're driving a Smart- to have a rolling survival warehouse in the trunk. But having a grab bag is essential if you venture away from your comfort zone.
Just a side note for the frugal. When I first put this kit together, I shopped around for the perfect bag and ended up spending about $15 at Kmart for it. Stupid. Go to your local Salvation Army or similar store and pick them up in quantity for 50 cents. Fill them with the basics and give 'em away- great holiday gifts- shows how much you care. Next one goes to my Dad. He's 86 and has been known to hop in the car and drive from SF to Portland with nothing more than a jacket in the back seat. He's definately not stupid, just used to a civilized and static world ("Call AAA"). It's his job in badass Oakland that worries me…
As far as tools for the car goes, I'd have a hard time recommending more than tire-changing tools and the basics- vicegrips, a couple screwdrivers, jumper cables- for the average motorist. What are you gonna do with a set of spark plugs for your '02 vehicle? Spare containers of fluids are good, though.
Always good to re-visit these preparedness issues, thanks. Aloha, Steve.