I have voted for 100-500 bitcoins but i see many people voted for over 1000BTC because it depends on currency of that particular country.
But according to currency in my country you will be a millionarie for sure even with 2-3 bitcoins specially after 5 years when price of bitcoin would be more.
Me too this is my assumption that we need atleast 100-500 bitcoins in able to be millionaire with fiat and let's just think that the stable price would be $1,000 -$10,000.
This is going to make your dollar millionaire or if not just convert it to your local currency and that is going to make you millionaire in your own country.