I think the problem is long term survival - finding ways to meet your needs with something other than supplies or guns. If just you are lumbered with lots of stuff, or lots of weapons there is going to be someone stronger than you or someone who will work day and night to get what you have, but if you have skills and knowledge, you are better as a friend to these people. So here is your list but with some inventions and ecological solutions I've seen used a few times in open hardware/green circles, where a lot of the idea behind it takes from open source directly - the idea that you have to share knowledge openly:
Blankets/sleeping bags: learn to sow, knit, weave old clothes to make new ones, or get inventive with plastic bags or tyres to make woven baskets and footwear. You can make plastic bags into a waterproof coat if you iron the bits together wrapping them first in baking paper. Tyre is really durable and can get you really far making stuff with it. All you need to make shoes is a relatively varied amount of them, inner tubes are nice and soft, a sharp knife and some nails. If it is really wet and you need impermeable footwear, bags to the rescue again: just wrap your socks in plastic bags and they will stay dry, avoiding infection, trenchfoot etc in a wet/flooded situation.
Drinking water:make a freshwater filter - all you need is sand, stones and somewhere for the water to pass through, in hot places using solar ovens to boil your water (and to cook food without needing to cut down a forest a year just to heat food), also I hear there are simple ways of preparing water for drinking by just leaving it closed in a plastic container in the sun for a couple of hours.
Food: organic and permaculture based farming. Permaculture is more of a way of designing a way of living - with limited resources, and it's what was famously used in Cuba after the USSR collapsed and no more food or fuel was available from there. They all lost weight but by embracing this and doing without fertilizers they still managed to avoid mass starvation and everyone was relatively comfortable, and a lot better off once the organic harvests kicked in.
Ovens: the simplest indigenous ovens are just a hole in the ground with a fire on the bottom, that you puyt the food in and cover up with leaves and earth(kind of a slow pressure cooker), but you can also, with some practice, make a kiln - a bread making oven made out of mud, which will last about a week, and produce some tasty stuff for quite a large group of people...
Refrigerating food so it'll last longer: a couple of clay pots and water will produce a nice effect where the sand absorbs the heat from any food you put in the smaller pot: put the small pot inside the big one, fill the rest of the big one with sand, and pour some water in with it. The water will evaporate and the sand will get a lot cooler. So you have a little refrigerator. Keeping your stuff in a cool dark place can achieve the same effect, but the pots idea is much more lightweight and mobile.
Lights: solar lights(the garden ones for example are usually to be found quite cheap), windup lights, small LED circuits that you can make yourself from sites like instructables or make magazine, a few carefully placed mirrors can bring lots of light to a room so that you don't need to rely on electricity working all the time or on having enough money to pay the bill. A couple of medium sized solar panels and a 12v battery from a car can give you lots of much needed electric power for night time lighting, recharging devices and all kinds of other uses.
Cooking: again solar ovens are brilliant and aren't only good for producing drinking water, but also for slow cooking some brilliant meals. Instructables this week is showing off a permanent design for one that rotates to follow the sun all day. Wood gas heaters are easily made from tin cans and some old newspaper or some sticks. It doesn't use up loads of fuel (which is fossil based anyway so creating more catastrophes the more you burn it, and likely to go up in price a lot in the near future). If you have a bunch of people you can figure out some bacteria based systems for turning leftover food and compost into gas, which you can then use to cook with the way you would in a traditional gas kitchen.
Improvised housing: the hexayurt is an open hardware design for a refuge that 4 or 5 people can put together in a couple of hours, and which can last years once assembled. You can make it from mostly recycled materials you can find lying around. There's also the factor-e farm people who have made a compressed earth brick maker, also open source, and I think you could slowly make a more permanent house using only mud and heat. Superadobe is basically bags of dirt covered with something more durable. All stuff you can use to avoid having to live in a shabby tent throughout a winter!
Entertainment/boredom: cook together, eat together, work and party together, learn to play and make instruments, teach each other stuff... Get some 12v batteries together and run a PA for a meeting or some entertainment. Nothing like a blitz to get people sharing what they know and helping each other out.
Radio, WAN/Wifi mesh networks - easy to do wifi to link up a small area - a block of streets for example so you can share emergency info like on looters, people in need or flooded areas etc. Smartphones can be SMS gateways for feature phones to piggyback on and share info. Ushahidi and systems like this are downloadable and easily installable and you can use them to deal with local emergencies, but I think also to plan longer term actions and community rules or information dissemination.
All this is being documented and used in places like appropedia, akvopedia, in the millions of DIY tutorials across the internet, and you can make much more than what is needed to survive just a short emergency, but to endure a much longer lasting situation of need. There's even a site right now in Japan that is slowly filling with DIY techniques for meeting basic needs in disaster stricken areas there.