STACK DICE!
Yes, dice. Be very bullish on dice. Post nuke holocaust/SHTF people will soon feel withdrawal symptoms from a lack of random number generation. In the future there will be a recognised Au

ie ratio and the little cubes will be very much in demand. Playing cards will fetch a nice price during trades, but dice are the end game's end game.
For trading:
coffee, tea, tobacco, ammo, knives, swiss army knives.
For hammering stuff or cutting very thick rope:
2 sledge hammers, 8 lb'ers oughtta do it. Make sure you got some hard-core pegs and rope. After all, if you've got sledges, you may as well have pegs and rope. Can't tie a hitch? Better learn.
Handy thing:
those recharging torches w/the built in winder that also comes with 6 phone adapters or so... 6 bucks from kmart i think.
don't wind them too fast while the torch is switched on or you burn out the LED lites... ( trust me )
Other stuff flowing off the top of my head:
get a parabolic mic... and then tell me if they're as much fun as I suspect. $35 eBay
brita water filter and many cartridges
Of course this is all useless unless you build a tower worthy of SHTF.
You don't need to go all out Circe or Babel, just out there in the bush, made from good solid stone and mortar, no doorway opening at ground level or more, just go the pulley type elevator thing and a 3rd floor entrance. Get some of them Israeli 3rd generation solar panels (Zennith i think ??) on the roof of the tower, and parapets are a must.
Anyone know if there are any recipie books written for cooking 'barking geckos'? There will be no shortage of em here in QLD, even after food runs out, but you will need light to attract the bugs that attract the geckos! <--- see above pointer re: recharging torch
If you forget everything except for 1 thing, remember to stack the dice.