The real best place would be to have your own oil rig like the nation of https://en.wikipedia.org/wiki/Principality_of_Sealand

Second best thing? Tough one, really depends but probably Vanuatu would be a great choice
they are already selling citizenships for BTC
https://www.bloomberg.com/news/articles/2017-10-12/bitcoin-can-buy-you-citizenship-in-one-of-the-happiest-countries

You can bet their govt will continue to become more crypto friendly with time (income makes govts more friendly)