Keep in mind the difference between state business law and state tax law. The tax status you choose for your entity under the federal check-the-box system doesn't make it that entity for state business law purposes. So, for example, choosing corporate tax treatment for a partnership won't bring corporate limited liability.
There is a trend for states to treat the entity chosen under federal check-the-box as the entity recognized for state tax purposes, but this is optional with the state.
State law may accept pass-through status for an entity (such as an S-corp or an LLC) and still impose a tax of some kind on the entity.
