B I T C O I N
Conceptualized and first implemented by the elusive Satoshi Nakamoto in 2008 and 2009, Bitcoin is perhaps the most well-known of crypto-currencies: at the moment of this writing, a single Bitcoin was worth well over 15,000 Euros! Some believe it to be a bubble, while others see its limited supply as making it something more akin to gold for investing. And then of course the fact that it is easier to transport makes it far more handy!
Its most feared nemesis is Ether, which does not wish to be a currency, but a smart contract platform.