Aren't the dodo's extinct?
just kidding.
If things got really bad, first on my list is a good "assault weapon"!
I like the AR-15. Ten magazines minimum.
Next a good bolt action rifle with scope, for big game hunting or offensive use. (like sniping.)
A .22 rimfire for scrounging food would be a must for me.
I would want a couple thousand rounds for the semi, at least a thousand for the bolt, and 5000 rounds for the .22, but these are minimums. If things really broke down, ammo would be the best barter item one could own.