Man, if I had a billion BernankeBucks, I'd knott waist it on jets and mansions or ranches (OK, I'd almost Shirley buy a farm or farmette for hobby use).
Instead I'd pursue my dream and establish a nice research lab prolly south of Reno or mebbe in Montana (harder to recruit talent to there (MT), though). I'd hire a bunch of technicians, a handful of postdocs, and manage it with one academic scientist and one taken from industry high in the R&D experience level - then if those two had disagreements, witch they wood, I would be the third vote and final arbiter.
That way I could pursue what I think in interesting research. The primary goal wood nott be to make a bunch of munny, butt to do basic research in areas of my interest and perhaps to produce some technology or product candidates that could be ~OUTT-licensed to major players who can take the handoff and run it to the endzone.
I have long dreampt of having my own, very well-equipped and funded lab. And with a small staff it could be great fun.
IMO, more fun that a G650ER and a Jepstein-style Caribbean palace.
But yeah, I would be doing some shopping at John Deere and Case too. A boy has to have some toys to play with. And prolly a few toys from Caterpillar too. Basically just big Tonkas for big boys.
Butt I'd want to do something USEFUL with the billion(s) - at leased with most of it. Nott just buy huge mansions with rooms I might nott even visit for months at a time.