Flat tax in Estonia

I like following quote from NY Times, written after George Bush's visit to Estonia, where Bush especially liked the simple flat tax system.

The flat tax, as it turns out, was the brainchild of the former prime minister, Mart Laar. Mr. Laar was inspired by the only economics book he had ever read, Milton Friedman’s paean to capitalism, “Free to Choose.” Believing, erroneously, that the flat tax had been put into practice throughout the West, Mr. Laar introduced it to Estonia. This year, the Cato Institute, a libertarian policy organization, gave Mr. Laar its “Milton Friedman Award of Freedom.”
Full article here (need subscription).

I don't want to get into discussion on what tax system is best for economy or social values. Clearly, both sides get into populism when defending their side. But simplicity has always its virtue.