Nice thread. I am going to quote straight from Henry George
http://www.wealthandwant.com/HG/ST_what_why_1890.html
1. It would dispense with a whole army of tax gatherers and other officials which present taxes require, and place in the treasury a much larger portion of what is taken from people, while by making government simpler and cheaper, it would tend to make it purer.
It would get rid of taxes which necessarily promote fraud, perjury, bribery, and corruption, which lead men into temptation, and which tax what the nation can least afford to spare -- honesty and conscience.
Since land lies out-of-doors and cannot be removed, and its value is the most readily ascertained of all values, the tax to which we would resort can be collected with the minimum of cost and the least strain on public morals.