Simple incorporation is really quite low cost, and very quick. CA is the worst I know of, with its $800 minimum franchise tax.
I just (re) incorporated in Oregon. I think it cost $150 (was $50 until 2009), and took about two days. IMO it's well worth it for legal protection from losing personal assets.
I don't have an accountant. I'll get one once I'm making money so consistently that it's not worth my time to do it myself. :-)
The minimum corporate tax in OR is $150. In 2009, they raised it from $50, and (I think) increased the tax rates across the board. The biggest change is that they now tax on gross receipts which means you can't deduct expenses.
Is incorporation premature optimization?