If you are into cryptocurrencies a day like today is a day to dream for. If you invest in solid coins with a solid strategy, this crash can only help you buy more of that coin you love.
Large market caps means people believe in the coin, the market is new and volatile, but that doesn't mean it will disappear. Invest in coins you research and aren't ponzy schemes most coins start giving a nice return between 2 to 5 years, depending on the target.
It should be like black week for crypto buyers! Enjoy the shopping!