The C corporation is the classic legal entity of the vast majority of successful companies in the United States.
Most lawyers would agree that the C corporation is the structure that provides the best shielding from personal liability for owners, and provides the best non-tax benefits. This is a separate legal entity, different from its owners, which pays its own taxes.
Most lawyers would also probably agree that for a company that has ambitions of raising major investment capital and eventually going public, the C corporation is the standard legal entity.
For more on business structures, see: The Complete Guide to Choosing Your Business Structure.