The items in the pictures are provided as examples only and are not necessarily the perfect product for your survival bag. This list is also not meant to be a complete list of everything you need. In many cases there are items on this list that you don't need in your survival bag. You should do your own research when deciding what you want in your own survival bag.
BackpackI recommend a backpack because if you are in a situation where you have to walk a long distance, it will be much easier to carry. I have seen several prepackaged survival bags that are in a duffle bag, or even a 5-gallon bucket. I don't think this is something that I would want to carry around with me for three days. A backpack I can just throw on my back and go. Portability might be an important factor in your survival. You never know. I have also seen many bags that are red or another bright color. I would select a bright color if you were trying to be spotted, and a black or cammo style bag if you are trying to stay hidden. Another option is to find something casual looking if you want maintain a low profile. I would personally opt for a backpack that is not a bright color. If you want to get someones attention use a flashlight or something. Also, make sure the backpack is large enough and tough enough to survive.
FoodThe idea here is to have at least three days worth of food per person. Some people feel that it is important to have something like an MRE (meal ready to eat), freeze dried meal packet (requires hot water) or something similar. If you are on a budget, there are cheaper alternatives such as energy bars. it doesn't matter what it is really, you need calories to survive. If you don't have food, you will get weak and this could lower your chances for survival. At this time, I am leaning towards freeze dried foods because of their shelf life, but remember that they need hot water to cook them.
WaterThis is even more important than food. I recommend getting water in some kind of a container and some kind of a purification system to compliment each other. The worst thing about carrying water is that it is heavy. Hopefully you will be able to find a source for some water that you can purify and filter along the way from a river or some sort of reservoir. In the mean time you will need containers filled with water. They sell water pouches, water boxes, but I think water in bottles is fine. I am not really worried much about the shelf life of water, but I will be rotating my water bottles every so often because I usually drink bottled water anyways. In addition to your containers filled with water, you should have something to put water in that you find along the way like a canteen or something like this. A collapsible water bag is a good idea because it takes very little space in your bag. Filtration and purification are necessary when taking water from a stream or similar water source. Simple filtration could be a clean sock or a coffee filter to get out dirt and bugs and things. Purification is to get out the bacteria that can get you sick. You can use bleach or water purification tablets, as well as boil the water. All will work. Make sure you are familiar with how to purify water with whatever process you use.
Mylar BlanketThese are also known as space blankets. These things work well, so I have been told by many people. They trap your body heat and keep you nice and warm and they take very little space in your bag. They also have mylar sleeping bags which also take very little space and also you won't have to worry about your feet sticking out from under a blanket.
Survival KnifeThis can take several forms. I prefer the knife that can do pretty much everything, but you should consider what you need wisely. You can do well with a Swiss Army Knife, a knife that has the fishing lure and matches and all that, or just a hunting knife if you prefer. You need to consider what you like and what you think you will need. There is really no right or wrong answer here. A knife may have lots of tools and such included, but there is no way of knowing everything that you will actually need. Do remember that you get what you pay for. Read reviews and such because a broken knife is not going to do you much good.
Hand Crank RadioA hand crank radio is an excellent edition to your survival bag because you will never have to worry about batteries. This will provide an excellent information about world events in a doomsday or temporary doomsday situation. Many of these have the ability to keep your cell phone or other device charged as well, although it would take some time to keep your iPhone charged and I would imagine that your arms would become quite large by the time you were no longer in need of this. Others have solar panels on them as well, but they are said to be quite weak so I wouldn't really rely on these for much power either but they will help you with charging your phone on a nice sunny day. The main purpose of this will be for the radio. Most of these emergency radios have access to the NOAA stations so you can keep up on current conditions as well. Many also have a flashlight feature which will save you one thing in you bag.
TentThere is a good chance that you may need some kind of shelter at night to keep critters and weather off you when you are asleep. Some people like to get the tube tents because they collapse so small, but my thinking is that these are pretty much useless. I would much rather get a small tent that zips shut and keeps the weather out and doesn't blow away with the first breeze. The problem with the regular small tents is that they are still quite large and may not fit very well in your bag. It is up to you how you want to do this. I am looking for smaller tents and larger bags myself. Even the small tents are quite large to put in a bag.
PonchoA flimsy poncho is probably good enough for most weather. It is a good idea to try to stay dry. A good downpour can keep you soaked for days especially if you are forced to wear the same clothes for a few days. A poncho is a great way to keep most of the water off you.
ClothesIt is probably a good idea to have some clothes that you can change into if your clothes do get wet or otherwise damaged unless you really like to be one with nature. It would be good to have a jacket or something in here too.
First Aid KitThis is always tricky because you never really know exactly what you will need. At the minimum bring some band-aids, antibiotic ointment, antiseptic wipes, tweezers, and a small knife. A soft case first aid kit that you get at the store should have a lot of what you need. I like the soft kits because they are easier to cram into your bag. As a bonus, get one that is waterproof so your kit contents don't get ruined.
FlashlightIf you want to see in the dark, you need a flashlight. Enough said. Sometimes the survival radio combos have flashlights too. I would consider having a few light sources of different styles. The little keychain flashlights are not a bad thing to have as well since you likely have your keys with you most of the time anyways.
Potassium Iodide TabletsIf you are worried about a radiation incident, you need some of these. 130mg Potassium Iodide Tablets are recommended for blocking radioactive iodine from entering the thyroid by saturating it with nonradioactive iodine. You need to have enough to take one per day as they come out of your system in 24 hours. Child doses are smaller.
Multifunction ToolWhile this won't replace your roll around toolbox, it will help you get out of a variety of binds. Since you never know what you will need or run into, a multifunction tool like a Leatherman or a Swiss Army knife will help you solve some of these problems.
RopeRope is an item that has very many uses. Alternately, you can use 550 paracord which is much smaller and lighter.
Fire StarterFire is a precious thing. You use it to stay warm, cook food, and to get attention. Flint and steel are not the only ways to start fires, but it is a good way that you don't have to worry about getting wet or anything like that as you would with matches. Matches are a good simple way, or weathproof matches, but they are a bit more expensive. Carrying a few different ways to start a fire is probably the best because fire is important and fire starters don't take up much space.
If you have any comments, ideas or suggestions to make this list better, please comment below.