I went into a potential urban survival situation once. In addition to what I needed for the job, I added:

Cartridge respirator with HEPA cartridges
HD leather work gloves
Explosion proof flashlight
5W handheld ham radio
Extra batteries and charger
Boots
Hardhat
Extra socks
Small camping towel
Alcohol hand wipes
Long sleave button up shirt
Leatherman tool

What I missed that I didn't take was:

Toothbrush
Toothpaste
Comb