I actually don't like the idea of a consumption tax. It implicitly says it's better to save than to spend, which means taxation is still a form of social engineering. Plus, what's consumption? Is buying stocks consumption or savings? Is putting money in an IRA consumption or savings? What about a savings account? Plus, then you have the issue of what institutions need to charge consumption taxes and under what circumstances. Then they become responsible for collecting taxes for the government.
I'd prefer almost a flat income tax. The first 10-20k you make shouldn't be taxed at all. Then, from there, 20% of the income you make above that should be taxed. So, for example (using 10k as the no-tax ceiling):
Person A makes $15,000 in one year.
15,000 - 10,000 = 5,000
5,000 * .2 = 1,000
Person A owes $1,000 dollars in taxes (6.7% of total income)
Person B makes $100,000 in one year
100,000 - 10,000 = 90,000
90,000 * .20 = 18,000
Person B owes $18,000 in taxes (18% of total income)
Person C makes $2,000,000 in one year
2,000,000 - 10,000 = 1,990,000
1,990,000 * .2 = 398,000
Person C owes $398,000 in taxes. (19.9% of total income)
In a sense this is a progressive tax, because it obviously results in lower tax rates for those with lower income, but it still imposes the same tax standard on everyone. And, unlike the current progressive tax system, it doesn't discentivise making money by throwing you into higher tax brackets (which means that even though you grossed more, your net income is lower due to higher taxes).
This actually works very well in, of all places, China. Because the government so actively polices its people, it has no interest in the actual process of taxation being time consuming and expensive, so they simply take 20% from your paycheck and let you keep the rest.