You may recall a few months ago where I used the example of some former Soviet states that were enacting flat taxes, and seeing massive economic growth (along with increased revenue) because of it.  Many people in the local blogosphere scoffed at the notion, and seemed to think this wasn't enough evidence.  Well, another former Soviet Republic, Georgia (that's right, not the state) has done the same thing and is also seeing fantastic results:

Effective January 1, 2005, Georgia (the country, not the U.S. State) adopted a flat tax of 12%, replacing its previous four-bracket system. The flat tax was augmented with a 20% tax on corporate profits, 20% on social insurance (reduced from 33%), and 18% (reduced from 20%) on VAT.

The new, simpler system has had a dramatic effect on economic growth, averaging 10% a year for the past three years, and taxpayer compliance. Tax revenue increased from 14.5% of GDP in 2003 to 22% in 2006, and should reach 24% in 2007.

This ought to be quite significant, and also ought to be a lesson for those who continually want to raise taxes higher and higher, and make them more "progressive".  Via Cato-at-Liberty.