If you're interested in what a lot of survivalists pack in their survival kits, they're often referred to as "bug out bags", e.g. http://www.aussurvivalist.com/bugout.htm.
In a survival scenario where you can only take a few items then your priorities would probably be (this taken from a survival course I did about a year ago):
- Warm Clothes
- Water cleaning system of some kind. (Puritabs)
- Something to store water in (ideally x2)
- Knife
- Something to light a fire with
In the 48 hour scenario the blog post describes then that should handle the bare requirements for survival. The fact that everyone in the scenario described prioritises food shows that they were really quite ill-prepares. For a 48hr survival period food shouldn't really be entering into your mind until you have everything else sorted.