I may be in the minority here but the Tomb is Empty because it's a fucking myth. Just like with every other religion that has used a Resurrection to woo its followers (see also, Judaism, Hinduism, Buddhism, Islam, etc.).

I said this in another response, but I subscribe to the academic theory that Christ was created by the Roman Empire to promote a peaceful prophet during a time where one of their major problems was an abundance of violent prophets advocating revolution. Kept the people in line.