I'm all in bitcoins right now, when the price of BTC is about to rise it is a good time to buy, but I think we will see more altcoin carnage before things change again.
But if I was going to buy now, I would go for altcoins that are around for years but lost most of their marketcaps. Ethereum and Litecoin, for example. Just look what happened with LTC price in the last BTC rally.
Bitcoin and top altcoins would still be the best investment to ever consider at any time, as they are still the most reliable coin that you can ever get with high volume, and even if their market cap is down right now, they are still having lots of recognition and they are the ones that people are buying more because they have real use product, we only need some bull trend for those coins to be able to recover fully.
In the future when bitcoin bull run starts, altcoins that are at the top are still the only coins that will ever rise along with bitcoin, most of those other coins that are not within the group may really never see much growth as investors would not pay much attention to them as they do for most of the coins that are within the top 10 to 200.