Back in the dotcom days after the bubble popped, there was a notable difference between the companies that died, and the ones who were able to scrape by and subsequently go on to thrive. That is, the survivors had a good value proposition in that they were able to save their customers money. I won't get into the details, but think of it like hod dogs vs t-bone steaks. In a down-turn, more hot dogs are sold.
So the question for you, dear reader, is the following: Do you know of an alt-coin that has a really good value proposition? What is it, and what gives it value?
First of all, I would say hold some Bitcoin as always. I know that we're talking about alts here, but the crash has brought some pretty good prices to buy at for bitcoin investors, and bitcoin is definitely one of the most obvious long term coins to hold.
Back to alts, I believe that you should have some anonymity-focused coins in your portfolio, because not a lot of people currently know the merits of these coins, and the prices of the biggest anonymous coins haven't been hyped up that much yet.
I suggest accumulating some XMR while it is cheap after the crash. Though don't buy all at once - buy equal fractions at a time regardless of the price, otherwise you might buy all of your XMR at a really high price.