Bitcoin, ethereum and neo are the best for me. Why? Because bitcoin is still the king. You just can't leave the king behind, seeing almost all of the coins and tokens are paired on it. Ethereum, because it has a working network and blockchain already that is used by many tokens. And lastly, I go for Neo, because it has a working network also that is booming now, but has not reached its full potential yet. I'm sure, with a short span of time, its real value would soon be realized. As long as the cryptomarket exists, these three won't die.