Batteries, charged...all the batteries you can toss into your car.
Batteries for radios, RDS, flashlights, AEGs...
A DC converter for your car is never a bad idea.
Grease pencil and acetate cover (or whatever clear binder thingys you can get).
Compass (or GPS...bring batts).
COMFORTABLE shoes for afterwards...
Fill ice cooler with drinks for afterwards
Hit/kill rag (usually a red rag)
general rags/bags for stuff afterwards