Even a million would be enough for me there. That would give me average yearly income of 70k. That would maintain my current level of living and I'd probably just keep getting wealthier still.
USD. I am using the 4% rule that states you can withdraw 4% of you investments annually and never run out of money. This assumes an average 7% market return and has a buffer for inflation and fluctuations. 400k per year is about double of what my wife and I make, so it woild allow us to have a cushy lifestyle.