I keep an emergency kit in my truck, but it's for getting home, not bugging out. I'll be bugging in.

Jumper cables
Tow strap
tire chains
assortment of wrenches and sockets
entrenching tool
pantyhose (emergency fan belt)
A few lengths of 12 and 16 gauge wire and assorted crimp connectors
Wire strippers/crimpers
Screwdrivers
Razor knife
hydraulic bottle jack
10x12 tarp
75' 3/8" poly rope
paracord
Flashlight

and in a backpack, in case I must walk

6 Powerbars
1 lb beef jerky
Katadyn Hiker water filter
Nalgene bottle
compass
Iodine tablets for water purification
sunscreen
bug repellant
spare socks and t-shirt
spare tennis shoes
hat
light jacket
Leatherman multi tool
roll of fishing line and assorted tackle
9 hour candle
space blanket
rain poncho
pencil and paper
bic lighters
magnesium fire starter kit
small mirror
fixed blade skinning knife and scabbard
more paracord
deck of cards
.45 w/ holster and 3 loaded magazines
$100 cash in small bills
12V rechargeable pocket am/fm/ weather band radio
extra 50 round box of ammo