This may be a little abstract and subtle, but I think it's what I'm trying to say. I'm pretty sure that the SS system exists for everyone in the US's sake. Although privatizing a part of it would *most likely* result in the rich getting richer (presumably everyone on this board is not filthy rich but you're not living on the street), it would also result in the poor getting much poorer. This is not an absolute result, but just thinking about the consequences of this beyond your own checkbook should dim most people's enthusiasm a little bit.
Let's imagine an extremely optimistic example. Just imagine that there's currently some small percent of people, say .1% of America (300 million people * .1% = 300,000 people) whose *only* source of income is social security, and forget about the reasons too, because they are diverse. Taking money out of the ss system would most likely result in the system going bankrupt a lot faster than it already is, or a reduction in payments, or something like that that would leave 20% of the people in a hospital because of poor health due to starvation/inability to afford cleaning supplies/whatever. Another 20% would just get evicted and live on the street, and the other 60% would somehow make it work. Now we've got an extra 60,000 people in hospitals not only taking up room there, but also using taxpayer medicare/medicaid money to stay in a vegetable-like state for months until one of their family members decides enough is enough and pulls the plug. There's also another 60,000 people living on the street, using taxpayer money because of the extra police, extra homeless shelters that have to be built and staffed, etc. Assume these people are evenly distributed among the 300 largest cities in the US... can Central Park hold another 2000 homeless people? Does your city have an extra 2000 hospital beds or staff to take care of them?
That's just a single, simple, optimistic example of one area of social disaster that would ensue under the collapse of the social security system. And, this whole thing about private philanthropy is bull. Where does the money come from? People like me and you. An argument cannot be made needs wouldn't go up if money were taken out of Social Security. Would you give charity proportional to the money you "gain" under private management? I would bet no. Ask any charity manager or volunteer that has tried to get others to volunteer. These organizations are already undermanned and can't keep up with demand for their services. A person would think that having more money in their pocket (an area also up for debate) would increase their quality of life, but it is not necessarily the case.
Finally, the whole argument that more money in people's pockets will increase spending and therefore increase tax revenue and benefit everyone is also bull. It was tried, it was called Reaganomics, and it failed miserably by plunging the country into the worst recession since the Depression. And oh yeah, caused a market crash.
So, now that I've put enough hurt down

, here's my rough solution.
1. Increase the retirement age/SS starting date. 65 is based on some old outdated data that showed the average age in America to be 68 or something and that most people died of disease. Nowadays, people are really healthy for much longer. There could even be some old age labor laws (I wouldn't support them), like people over 65 can only work 35 hours/week, over 70 => less than 30 hours, etc. Although it's kind of annoying to have to work for five to ten more years, it's very possible and quality of life for everyone will go up.
2. Make education careers prestigious. Teachers make squat, and therefore don't get a lot of the "best and brightest." There are a lot of smart people out there motivated by money (see previous N posts) who go into engineering or medicine but who would seriously consider teaching positions if they started at the same level as engineers or doctors. Sometimes throwing money at a problem doesn't work, but raising the entry level teaching salary would help bring better teachers into schools. I would say that improving the educational system is one of the easiest ways to lessen some of America's social problems (homelessness, a shortage of technically skilled workers, the racial divide), which would reduce the need for social security.
So, to conclude, I would say that although privatization of social security seems like a good idea, it would create a lot more problems than it would solve. It also seems to me that the only "problem" it's solving is that people think their money is going to waste, and they want to bail out while the system still isn't bankrupt. It's really only in some skewed sense that our money is going to waste and the government is taking it all without giving anything back. We are all benefitting somewhat from the government having our money... it's just kind of transparent to us. If the benefits were gone, we'd notice it. And, no amount of benefits we could create for ourselves by having more money in our pockets would be able to reproduce the benefits the government provides.