Simplicity

Complexity is a hidden tax amounting to more than $100 billion. This is the cost of tax preparation, lawyers, accountants, and other resources used to comply with the Internal Revenue Code. The Internal Revenue Service even admits that the current tax code requires taxpayers to devote 6.6 billion hours each year to their tax returns. Yet even this commitment of time is no guarantee of accuracy. The code is so complex that even tax experts and the IRS often make mistakes. All taxpayers, from General Motors to a hamburger-flipping teenager, would be able to fill out their tax return on a postcard-sized form, and compliance costs would drop by tens of billions of dollars.

A flat tax or fair tax would yield major benefits to the nation, including:

Faster Economic Growth.
Instant Wealth Creation 

Fairness
An End to Micromanaging and Political Favoritism
Increased Civil Liberties
Global Competitiveness