I've got a bag full of bungee cords in one of my cars, and can't think of a time I've ever used any of them. Well, to be fair, I can't think of a time I've ever been stranded or broken down either.
ETA: One time I used the bungees to bungee down my CB antenna so the truck could fit in a parking garage. I've since remedied that and just installed a hook.
"There are no finger prints under water."
In all seriousness. Carry hand warmers and Mre heaters. They thaw bottles just fine
Your water will thaw when you bring it into the cab of your car or truck. While you want at least a gallon of water, I like to keep it in quart- or liter-size bottles (usually from washing out and reusing bottles from G2 or similar drinks). I prefer candles or homemade paraffin heaters to sterno -- no poisons or leakage to worry about (although you don't want to leave them in the car when things get warm). Make sure you have waterproof matches or a lighter. Add a fleece blanket to your inventory -- doesn't take much room if you put it in a compressible stuff sack.
If you have to light anything in the car, be sure to crack the windows just a tiny bit to let exhaust gases out and fresh air in.
Just in case things get really deep where you may get stuck, consider some sort of orange flag/streamer and a way to hoist it up over the car. If you have a CB antenna, it could be tied to that, for example.
Oh, and get a set of tire chains to keep in the car. Hopefully having those would make the difference between getting stuck and getting home.
Shot Works Pro... It's better than scrap paper!!!
You can use the discount code 'Take5' for 5 bucks off.
A WARM sleeping bag, and a good pillow. If you're going to be spending some serious time in your vehicle, you might as well be comfortable.
As previously mentioned a folding shovel should be included and even throw in a bag of sand if you have the room but don't have chains. These two things can really help you dig your car out if necessary.
Also...it has been mentioned once, but I am going to say it again...SOCKS. Your feet will get wet and you will need dry socks.
And get a tow strap. I truck capable of pulling you out may drive by, but they might not have a strap. I have seen this happen more than once.