Also, not sure if I remember reading this or not earlier in this thread, but I think it is important to mention again even if it was.

Your bag should be customized to your AO. For example, if you live in the California forest region, you may consider putting a fire blanket or other fire emergency equipment/treatments. If you live in Las Vegas, you may want to carry more water and learn how to extract water from the ground or plants with green house/condensation techniques and carry needed materials.

When in a water poor area, remember to check the sodium content of your rations. You want low sodium if you know water will be scarce. U.S. MREs are very high in sodium and are designed that way on purpose. The MREs are designed to be very high in calories (about 1200 a meal) to keep us fueled while under constant manual labor. They are high in sodium so we have plenty of electrolytes while constantly hydrating. If you do not have the luxury of constantly hydrating, MREs are the wrong choice of food (they make you need more water). Go with something like the Mainstay rations Arch suggested or Datrex. Both are designed to be low in sodium since they are emergency rations not MREs. Yes, MREs are better tasting and have a larger variety, but they also are not as calorie dense and therefor take up more room and weigh more per calorie.

There is no way you can carry a reasonably weighted bag and be prepared for every environment on Earth, so research your area and what types of disasters are inherent there and prepare accordingly.