Ownership = Power. Power = Motivation. Motivation = More/Better production. What's more, it's production that fits what people actually want (what they will pay for). This leads to my second point: rich people's money isn't wasted, it's re-invested. Sure, some of it goes to private jets, but that's a small price to pay for the efficiency and innovation* they add to the system. In other words, $1,000,000 in the hands of one very smart person is much better than $1 in the hands of a million people who spend all their money on smokes and beer anyway--or even worse, in the hands of a spendy government bureaucrat.
* Don't discout the value of inovation. We are four times richer than our great grandparents, and it's not becuase we work harder; it's becuase someone invented a better way of doing things (check out the industrial revolution--it's why we're not all living in dirt huts, and why we're wasting our time reading Slashdot instead of hoeing our corn and dying of cholera). And don't get me started on machines taking people's jobs. It's not a zero sum game here. Machines give us the time to do better things, like go to school and learn how to make better machines.
You'd think that I wouldn't have to explain this on Slashdot where people are more likely to spend hours writing a program/kludging a machine to do something, than do it by hand in 20 minutes. But stand back the next time they have to do it, or scale it to millions.
Get over the commie/socialist thing, it doesn't work. Free markets/free minds/more food/ and cooler stuff. It's the way to go.