I disagree with the water part. What if the best plan of action is to stay inside and lock the doors? Keep water in your house, cheap, easy, no reason not to. Thats like saying "don't keep ammo, you can always get some later" , not good planing IMHO. Water sources becomed contaminated, filters can get lost or broken, or left behind in a hurry, not to mention, a filter still needs water to filter, without that, its an expensive stick.

I keep at LEAST a gallon in every vehicle (along with a roadside hazard/emergency kit). I have a 2 liter jug (cheapo from walmart with handle) of water that goes with me EVERYWHERE, to work, to play, to my buddies house. Its part of my EDC, and it is constantly recycled because I try and drink all of it everyday to stay hydrated. Plus the emergency food bars are lighter and better for hoofing it if you ask me. I keep a few MREs in my bag, but only the entres and the heater.

Best way to stock up on water without breaking the bank or looking crazy is just to buy a few extra gallons everytime you go shoping. If you use it regularly, always add your new ones to storage and use the oldest jug you have first. The supply is always revolving and acumulates slowly over time.