I've been thinking a lot about 72 hour kits. Most of us have the items on most lists, but they are spread throughout our homes. The more I read and learn about emergencies, the more I believe in a kit that is immediately ready to throw in our cars, or be carried away from our homes.
I've seen a lot of lists from FEMA, Red Cross, LDS blogs, and some serious Doomsday groups. Here's a good basic list with some extras added. Please add any extras I may have overlooked in the comments section.
1 - Water. You can live without food for three days, but you cannot live without water. Pack one gallon per person per day. Don't go out and buy all one size. Some can be in large amounts, some should be in small amounts and easily carried by children. Water filters, sterilizing drops, pills, etc. can supplement your amount, but do have some ready water packed.
2 - Food. Pack foods that are ready to eat and don't need to be prepared. Pack high energy foods like peanut butter, crackers, granola bars, etc. Pack treats like hard candy, gum, and instant cocoa. If you're using MRE's, consider their water activated heaters. Pack utensils that can be reused and thrown away. Pack dehydrated meals. Pack extra water if needed for these type of foods. Pack specialty foods for infants or special diets. Try for 2,000 calories per person per day.
3 - First Aid Kit. There is a lot of discussion on what should be in here. Think of the basics first. Bandaids, Neosporin, Antiseptic Wipes, tweezers, Gauze pads and tape, Feminine Menstrual supplies, Latex Gloves, Hand Sanitizer, Thermometer, Non prescription drugs, and Prescription drugs. Consider adding sunscreen, lip balm, burn cream, small sewing kit with scissors and safety pins, Ace bandage and clips, instant ice pack, CPR shield, Ipecac and Activated Charcoal, Face masks.
4 - Basic Needs Supplies. 100 hour candle. Waterproof matches, Solar/Battery/Hand Crank Radio with AM/FM/Short Wave/NOAA capability, Flash lights, Light Sticks, Batteries, Utility Knife, Pliers, Collapsible shovel, Duct Tape, Plastic Sheeting, Compass, Whistle, Flint, Cash in small bills, Pencil and Paper, Card games and puzzles, Aluminum Foil, Ziplocs, Signal Flare, Local Map showing towns, roads, waterways, and terrain, Clorox Wipes, 5 Gallon bucket with lid, trash bags, Disinfectant. Consider if you will need plates and cups based on what food you have packed.
5 - Temporary Shelter Supplies. Small tent and stakes, sleeping bags, Space blankets,
6 - Clothing. Sturdy shoes, Rain gear, hats, gloves, Thermal Underwear, Underwear, Socks, One set of shirt and pants per person, Coat/Jacket.
7 - Personal Hygiene. Toilet Paper, Comb, Hair bands, Soap (Consider Dr. Bronner's type soap that can be used for plates and is biodegradable too), Shampoo/Conditioner, Disposable Razor, Tooth brushes and paste, Wash Cloth, Hand Towel, Contact case and solution (if applicable).
8 - Papers. Copies of: Birth Certificates, Insurance, Immunizations, Phone Numbers, Will, Passports, Social Security Cards, Bank Account #s, Stocks, Bonds, Investments, Credit Card Accounts, Household Inventory, Marriage Certificate, Scriptures, Patriarchal Blessings, digital copy of genealogy. Can add copies of photos in digital form.
9 - Gas Wrench. Before you leave your home in an emergency, shut off Main Power switch, Main Water supply, and Natural Gas at the meter.