I'm surprised none of you have yet made this answer - none of the above. There is no one 'best' form of schooling. What's best for one student may be bad for another. Any of these forms of schooling can create a thriving learning environment or fail miserably at that goal. If there clearly was one best way then that would probably be the only one practiced.
Home schooling = a way for fundies to shove creationism into their kids' heads.
Actually, I know of one case where atheists were basically forced to home school their kids because the public school environment was filled with enough anti-atheist Christians that keeping their kids there would be bad for them. While home schooling can be used as a platform for indoctrination, the same can be said of public and private schools.