Gold and silver would be the ultimate store of value in a post apocalyptic world. Guns, ammo, food, and water are obviously more important. I bought a couple of katadyn pocket filters years ago although I no longer think society will collapse, it's still nice 'just in case' to have something like that. I don't have any food stockpiles so I wouldn't last very long. I also don't have a 'killer instinct' and have no reason to go around looting and pillaging to survive. If I ever have a wife and kids, of course that would change.
Nonetheless you're fooling yourself if you think gold or silver would not have value. They are the ultimate, publically known stores of value that go back a thousands of years. They make a great PART of anyone's survival prep. I'm not saying they should be the sole focus, or the only thing you have... food, toilet paper, water, guns, and ammo should make up your foundation... gold and silver.. merely a place to put some spare cash.
The worst possible scenerio would be a large scale EMP event, perhaps from the sun, that wiped out everything electronic on a global level. That truly would be devastating. Only items protected by Faraday cages would still function. I wonder how many big tech companies have protected their valuable manufacturing ability with such protection? Probably not many. The major issue is our electrical power grid being outdated and the virtual lack of any extra supply of large transformers which would be destroyed from an EMP event... without transformers any electricity you do generate is not going anywhere. Of all the things we blow our money on, or fragile electrical grid could be described as a ticking time bomb.
http://empandsolarprotection.com/2012/04/which-is-the-greater-danger-a-solar-flare-or-a-nuclear-emp/"In 1992, after Hurricane Andrew hit South Florida, every spare small transformer in North America was used restoring power in South Florida. This was followed by a one-year world-wide shortage of small transformers. The world is woefully unprepared to restore even a tiny portion of the world’s electric supply following a massive CME."