Can't add much to what was already listed above except:
light sticks and a string, swing one in a circle at night and it really helps you get spotted from the air
starting fluid (reseating beads, flame thrower for animal defense and fire starter
wrist rocket sling shot
Magnifying glass (start a fire)
poncho (even a cheap one is better than none)
Biggest heavy duty trash bags you can find (one inside another can make a good emergency sleeping bag when lined properly as well as dry sleeping)
Coffee filters (filter the big stuff out of water, passable dust mask when used with tape or a package of cheap resperaitors will do both too)
Tampons or sanitary napkins (if stranded with a female and she needs them she will be extremely gratful and they make good large capacity bandages)
I could go on and on but here are some good links:
http://www.bestglide.com/index.htm Good source of materials, small aircraft related stuff, take a look at their articles page and print some of there info, throw it in your kit, when under stress just being able to read something can help your thought process a lot.
http://www.quakekare.com./ another good source of shelf stable water and ration bars, cheapest I found when assembling my home and vehicle kits.
Use your imagination and keep your eyes open, I find stuff on close-out and on the dollar rack at target and wally-world all the time! Goodwill is a good source for cheap bags for storage and other stuff. I once scored 72 hour survival packs for my cars complete with stabilaized water pack and food bars for 2.98 ea. Found them on line for $30.00 so it pays to keep your eyes open.
Actually it can be fun putting this all togather.
*edit* This stuff is in a large ALICE pack that's typically strapped to the front passenger seat. If I were to go off the road, it's reachable and if I have to hike out, I can put it all on my back.
