Not really

The countries with the highest living standards, and the lowest gap between poor and rich, are also the countries with the highest tax rates.

Should read the comments by most of the pro-flat tax people here.

Most of us that are for flat taxes believe that those making underneath a certain income should not have to pay taxes at all. In America, you can make $200 a month and still be required to pay approximately 20% to the government today, to get it back next April. This causes those that are poor to acquire loans or other forms of debt to survive today, while they wait for the government to tell them they can have their money back.

We need a flat tax system with a minimum threshold that one must make in order to pay taxes - e.g. $40,000/yr. Furthermore, we must ensure that there are absolutely no loopholes. The issue with our current American system is that the most wealthy do not pay their fair share because instead of politicians closing loopholes, they raise taxes...Which only hurts some of the wealthy. In America, we have a $350 billion USD/yr compliance industry to pay accountants to figure out our tax code. If we had a very simple flat tax, the money could be invested in better areas of the economy, and lift the burden of the poor and middle class from needing accountants and expensive tax software to figure out what they're supposed to pay.

In such a system, we could bring in a decent amount of tax income for the government (albiet not enough to pay for their runaway spending). The American tax system is atrocious, and it needs fixed. Making it simple and easy to understand would ensure that accountants and the wealthy could not leverage loopholes to pay less. Even at a flat 20% of income, the wealthiest 1% would actually pay more than they do now, at 35%.

Oh, and while we're at it:

• Privatize pension plans in America
• Offer vouchers to every child in America to pick their own schools based on merits, and not districting
• Privatize medical pensions in America (medicare)
• Get massive cost-saving government interferrence out of medicine all together
• Reduce military spending
• Decriminalize drugs and let 50% of our prision population free

....Of course, it'd save us too much money to do this, and give us a better country in return.

If you are talking about Western nations, maybe.  Although highest living standards is a good thing where as the lowest gap between poor and rich is neither good nor bad.  Maybe it is good to lower the gap in a nation the frequently has revolts, but in general there is nothing special about it.

A flat tax is just another name for a fat cat tax.

Who has more to gain from funding a military that protects America's oil and trade interests?  The poor or the rich?

Who has more to gain from funding roads and bridges to ensure the safe delivery of goods across the country?  The poor or the rich?

Who has more to gain from funding education and health care so they can have an educated healthy pool of workers to hire from?  The poor or the rich?

Who has more to gain from funding the bailout?  The poor or the rich assholes on Wall Street that got us into this mess?

etc. etc. etc.

Rich people get more out of America (or any stable government and economy for that matter), so they should put more back in.

Based on that logic we need to start taxing outside buisnesses.

Afterall, a buisness in China that sells stuff here benfits just as much... if not more so. (What with the no taxes.)

Of course, the true target should be zero income tax. I know a few states don't collect income tax (Florida, New Hampshire, Washington, off of the top of my head), any countries out there have zero income tax?

Good question. 

Yes, http://en.wikipedia.org/wiki/Tax_rates_around_the_world

Quick, everyone, to Monaco!