My favourite life-changing altcoin is Ethereum...
There are a lot of smart contracts already circulation in Ethereum network and ETH must be used for their transactions.
I like this coin concept and future PoS algorithm.
What seems iteresting also for the future is Telegram TON - GRAM coin. So I hope there will be also ICO for normal users as we are, not just for rich investors.
Their global network blockchain project is really promising. I will definitely buy a lot of them if they will be released for public.