I don't think it is possible to be too rich. You need rich people to buy rich things, and pay for stupid experiments that no one else would invest in. Branson is a great example... Sea bed exploration, commercial travel to the edge of space etc...
Hell, often the Richest in the world, are the most sensible with money.... Look at Buffet.
That said, whilst I don't think it is possible to be too rich, I do think it is possible to not respect the money you have. I don't neccessarily agree with the concept in the OP of some spoilt teenager having no understanding of money. That said many multi-millionnairres are good at teaching their children how to deal with money... Just some aren't. Peter Jones is a good example of someone who is able to. I think his system is that he's set up a trust fund for his kids, and he doubles whatever they earn. If they do a particularly socially beneficial job that is underpaid (nurse for example), he triples it instead. But yeah, other parents aren't quite so good at instilling the same kind of respect for money.... (Lionel Ritchie)
If I was a multi-billionaire, I'd probably run an interesting business of some kind, no idea what though, and then I'd probably spend a lot of time learning to do interesting things. Doing what I wanted. Visit the wonders of the world, go scuba diving in the Galapogas (again), go to Patagonia, hell, go to Antarctica. Buy a Les Paul, Spend a year driving a 67 Mustang across America, and then put it back in my garage of cars for the rest of it's life, just to be looked at and admired.
kd