It's not just a division between people who are happy with some amount of money and people who always want more. There are also people who are unsatisfied because they have a constant need to create things. I believe most of the really driven people in Silicon Valley are of this type, actually.

That is definitely true, and probably a big differentiator between Silicon Valley and Wall Street. In Silicon Valley, there are those who are rich 'accidentally', simply as a side effect of doing something they really wanted to do. You see the same in the entertainment business, as well as in 'leisure' industries, like mountain bike and surf board building.

Once you go beyond these 'legends', to the, I believe, much larger group of people described in the article, this no longer seems to hold, though. The "legends'" possibly inadvertent, yet widely publicized, financial success, seems to have drawn to The Valley many more that ARE in it for the money, and these are the ones I doubt will ever be content.

It's interesting that you think that people who are really driven can end up being unsatisfied because of that nagging feeling they have telling them there's more to be done.

I would think that having a lot of money would give you the freedom to choose your work, and the ability to wake up every day and work on something you feel passionate about would make you happier. I guess you could say that you don't need a lot of money to do that. But it would make it easier.

what about if you want to create good children? 60 hour startup work weeks can't be good for that, can they?

You can't "create" good children. They'll resent it when you care more about their life than they do.

I suspect people who work 60 hour workweeks have a tougher time supporting their children (emotionally, not financially), but stay-at-home parents also have trouble setting examples for their kids. It's all a tradeoff.

The people interviewed seemed genuinely concerned about money, rather than simply being smitten with what they're doing. Also... lots of talk about N hour days, with large values of N. I know I don't do my best creating when I'm completely knackered from too much work.

Some people are motivated by what money can buy others are motivated by the freedom it can bring. Someone motivated by freedom will put in just as good an effort as someone motivated by material wealth. The bottom line is that you are motivated.