...I might buy you a monkey.
Really, though, $1M as a lump sum after taxes is something I could make real use of: pay off debt (mine, family's, others) and do a few things with my house, then bank some. (I probably wouldn't be nearly this effective, but, I like my job, and don't care as much to maximize. )
For $2M I'd be pretty much set for life.
At $5M, so too would be my family and others.
Beyond that, it's really, really hard to keep coming up with things to spend money on that aren't ridiculous, or so extravagant that I really couldn't justify it. So I'd probably give it all away.
Mittens made $17M after taxes in each of the last two years. I cannot comprehend the level of greed it takes to see that income as anything other than an opportunity for some serious charitable giving, or something to start businesses/companies with or...something other than personal wealth enrichment and exhibition. I just don't get it.
As a side note, the lady writing at the link shows just how much easier life gets as you get more money: at $1M she manages ~$34k/year, in passive income, but doesn't buy a bunch of things for herself. If she were to double that, she could more than double her income, or she could use some fraction to buy some security, something like establishing her dwelling so that her expenses would be lower (and still have much more income).