Bitcoin is the living legend among all coins in the whole world. But as for me since i don't have enough money to invest in bitcoin, i will go for etherum and in my money in ethereum.
It does not matter how much money you have. You can buy many Satoshi. I am holding both cryptocurrencies. I believe that Ethereum and Bitcoin will give you the highest profits if you do not sell them at least for a year.
These two coins, bitcoin and ethereum is worth keeping in long term, my style is I buy coins when I see the market price go down and make a decision of holding atleast six months, but if the price during that period is still low, I keep holding it until the price returns to its normal high price.