Yes, pure silver is pure silver. Just American Eagles are well known and easy to sell but the flip side to it is you pay a pretty good premium when you buy them and will only get back probably half that if you resell unless of course the price of silver climbs above your premium price.
The best bang for the buck are stuff like 10 ounce and more bars from Johnson matthey. They will have the lowest premium but bars are a lot harder to store than coin bullion. Can just load coin bullion into tubes and be done with it.
I would personally do something like a 10% gold to 90% silver. And buy small denomination gold like 1/10, 1/4 and 1/2 ounce. You pay more of a premium but if the world goes to hell, it will be easier to use smaller gold to buy stuff than 1 ounce. And the silver would be good for even smaller stuff. Plus gold is easier to pack around than silver. Also stocking heavier into silver will allow you to trade off to gold when the gold to silver ratio goes lower and using low premium silver will net you a better turnover when you do it as you wont be losing too much on the premium.
But of course the biggest things you will need will be blankets, food, water, guns and ammo...but gold and silver wont hurt too
Remember when gold to silver ratio is high, buy silver...when low buy gold or if silver heavy, trade in some silver for gold.