rubber gloves, tire gauge, 3 flares, triangle reflector, gaffer's tape, string, tow strap, small cheap first aid kit that gets replaced each year, tiedown straps, extra heavy duty lug wrench, half roll of TP, sharpie marker, extra oil filter & washer, taillight bulb, red plastic tape for instant taillight lens, a couple of contractor grade trash bags, pocket knife, wind-up flashlight, compass, whistle. I just got a mini 12v air compressor but I haven't decided if it is going to live in the car or the garage.
In winter I usually add a small snow shovel, truck-size brush & scraper, old set of snowpants, cheap fleece blanket and an emergency start battery as my car tends to spend weeks at a time in airport parking lots.
I like the disposable camera idea. I used to have one in an old car, gave it up when camera phones were exciting. But the more I think about it, the more I think I want film in my life again.
I should also include a paperback novel for entertainment's sake. Title suggestions anyone?