Bit late on this bandwagon but started putting together a list so don't want it to go to waste

some already covered but some info on seeds and how long they last along with a few foods.
Long Lasting Foods & Seeds
Obviously if a disaster does not happen in 2012, then the same would apply for a disaster in the future, but generally these foods and seeds do have a shelf life so rotation would be needed at some point.
I found a few articles and broke them down to what is below, basically showing the name, time it can last, nutritional factors and the availability of purchase and usability. I haven’t included anything less than 3 years survival time, though corn and pepper seeds have two year lifetime if you wanted to know.
Seeds
If you can relocate to somewhere with fertile ground then obviously seeds would be handy as you don’t have to completely rely on natural produce in the surrounding areas. Most seeds have a fairly short shelf life but some varieties can last up to 5 years, though this isn’t optimal so the sooner the better in most cases.
Seed/Plant: Radish
Shelf-life: 5 years
Nutrition: Vitamin C and anti-biotic properties
Availability: In the UK places like B&Q offer these at around 50p and you get 450 seeds from that. It may be worth buying a few packets per year so that you always have some whenever a disaster strikes. This type of survival is so cheap, you may as well!
Seed/Plant: Cucumber
Shelf-life: 5 years
Nutrition: Vitamin C and Potassium
Availability: A few pounds per pack and can be found online and I’m sure in shops like B&Q.
Seed/Plant: Tomato
Shelf-life: 4 years
Nutrition: Vitamin A, C, and K, plus Calcium
Availability: Always available online and in the garden centre type shops as mentioned above. Generally they need warm conditions to grow and ripen properly, but it’s another option.
Seed/Plant: Cucumber
Shelf-life: 5 years
Nutrition: Vitamin C and Potassium
Availability: A few pounds per pack and can be found online and I’m sure in shops like B&Q.
Seed/Plant: Spinach
Shelf-life: 5 years
Nutrition: Anti-oxidants, Vitamin A, C, E and K, Iron, Calcium, Protein….lots more!
Availability: Easily available, a few pounds per pack. Obviously fertile ground needed and right climate, though they were originally grown in Asia, they’re grown in England and other places so worth a bit of investment.
Seed/Plant: Carrots
Shelf-life: 3 years
Nutrition: Sugar, Vitamins C, D, E and K, Calcium, (bit broad) Minerals.
Availability: Easily available, like most root vegetables.
There are more like beans, cabbage etc, but I thought I’d put a short list together to give ‘food for thought’…..for about £10 you could get a pack of each of these and not have to worry for 3 years that you have over 2000 seeds, so it’s definitely worth the buy.
Foods
Generally you can freeze a lot of things, but moving a great distance would ruin the majority of these foods unless you have a novel method of keeping them frozen. It may be an ice age, in which case you’re winning…until you run out and the seeds you bought from B&Q can’t be planted! :O
Not going to detail as much but short list is:
Rice
Freeze-able
Pasta
Dehydrated Fruits
Honey
I imagine Twinkies going by the film Zombieland as well

Canned foods
Nuts
MREs (meals ready to eat) – US army gives them to soldiers but available on eBay, though fairly costly. They do provide around 1200 calories a go though which could be very useful. Plus they can be consumed over 3 weeks according to good old Wikipedia, which means they can be shared or at least if you’re running short you have some time to try and find more food.