It's hard to say it's good or bad, but mostly it's unnecessary. You should talk to a tax accountant in your state, but generally for a small company the added expenses that come along with creating a foreign corporation offset teh advantage you'd get by avoiding state income tax on the corporation.
Remember that the corporation still has to pay federal income tax, and any money you pay yourself from the corporation as salary, dividends, owners' equity, or any other distribution, is taxable on your individual state and federal returns -- and you may have to pay a fee to your own state to register as a foreign (out of state) corporation doing business in your state.
The main advantages for Delaware incorporation involve judical precedent and specific legislation, and apply to publicly-held corporations. For a small closely-held corporation there's usually not a compelling argument for it.
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