Forbes: The Anachronism of State Income Taxes, by Peter Ferrara:

Nine states survive perfectly well with no state income tax at all. These include large states such as Texas and Florida, medium-size states such as Tennessee and Washington, and smaller states, in terms of population, such as New Hampshire, Nevada, South Dakota, Wyoming, and Alaska. This policy should now be extended to the other 41 states.

Income taxes are the most economically destructive of all taxes. That is because income levies tax directly the reward for work, savings, investment, and entrepreneurship. With the reward reduced, the incentive for pursuing these economically productive activities is reduced. The result is less work, less saving, less investment, fewer new businesses, less business growth, less job creation, lower wages and income, and lower overall economic growth.