1) Get one of these:Combat-Survival Prius; 'nuff said.
2) Get as much guns and ammo as you can, because face it, we all know that God ain't coming to save you.
3) Get as many solar panels/wind turbines as you can, because face it, we all know that God ain't gonna keep that Counter Strike server running.
4) Use your 401k (psh like any of you have one), before Wall Street fat cats completely destroy the retirement funds of middle class America, to invest in a Svalbard Global Seed Vault to ensure that our ancestors will be able to re-create the bio-diversity of Earth after the Dark Ages that are sure to come.
5) Invest in a homebrew beer laboratory. This segment of chemistry is perhaps the most vital to humans, plus if you are able to become a post-apocalypse Beer Impresario, you will be the richest, sexiest, most powerful human in the inevitable doomscape of the coming future.
Ummmm... beer, video games, food.... what else is there really? Let us know in the comments if you have any other pertinent suggestions. Anyways, take these words to heart PS readers... we wish you luck, and maybe we'll see you at the 2020 Praise Science Post-Apocalypse Reader/Zombie Meetup Extravaganza!!!