Buying real estate or land would go towards your net worth, and putting your money into private companies would be a problem. But the IRS knows how much you are worth, and I wouldn't want to go to jail for tax evasion.
Well, since Bill Gates net worth is invested this would be hard to do. He doesn't have his $70 billion dollars sitting around in so many shoe boxes full of hundred dollar bills that he can just go out and give away. In order to divest himself of his net worth, he would need to sell off Microsoft and his other holdings. What if there weren't enough buyers? There certainly wouldn't be enough buyers at the current price. If Bill Gates called his broker and said "Sell $xx billion in Microsoft!" the stock value would probably fall like a rock. Who knows, Steve Jobs might buy it.
But, let's say that Bill Gates gave some incredibly large bonuses to the workers at Microsoft. I bet some of the programmers of Windows 3.1,
There is certainly no bonus deserved by anyone who programmed Windows 3.x 95, NT aren't millionaires. And I was thinking more a log the lines of keeping the money within the company, just spread it around more. If you devide Gates' wealth (69.75 bil/3.4 mil) among every person in Oregon, they would only get $20386. Most people would spend it, and given enough time, I'm sure that someone would create something that everyone would buy.
Most of the windfalls would probably get spent on imported cars and consumer goods, thus ending up in Japan, Singapore, China, etc.
People might quit, or be able to get better jobs. They might be able to start their own business or volunteer to make the world a better place. They might be able to do things besides working.
A $20,000 windfall would be nice, but I don't think it would cause me, (or most people,) to quit my job. It's not enough to start most new business from scratch. Certainly not enough to outfit even a small coffee shop or auto repair garage. I think a lot of people would buy new cars, remodel their homes, pay down debt, put it in college savings or their IRA. I doubt if this would make a huge permanent change in most people's lives. Except for Bill Gates, of course. 
I think the figure your looking for is the top 10% of the richest Americans own 70.9% of the wealth.
http://www.osjspm.org/101_wealth.htm There would be a revolution like the French had if the top 1% held 99% of everything. But, we are heading that way.
http://moneycentral.msn.com/content/...bes/P61243.asp
Inflation would be a problem, but the government would collect more taxes and take money out of the system by hopefully paying down the national debt.