I would say Christianity.
To those that would say the difference between mythology and religion is faith and that religion requires faith while mythology doesn't, I would reply that people that believed in Thor, Zeus, et al also had faith in them until their belief systems, much as Christianty has been, were disproven.
Well, actually most of the people that held onto those earlier religious belief systems actually did so until the Christians forced them to convert at pain of being burnt alive which is why I would say that Christianity (and the Judaeo-Egyptian traditions that it grew out of) has been the most influential mythology.
Whether this post will result in some religious debate as someone above said it would is really up to the true believers and their actions as I'm just stating the facts. If you want a scholarly text that also says Christianity is a mythology check out J. G. Frazier's The Golden Bough and Richard Dawkins' statement to the effect that everyone is an atheist it's just that the people that are commonly known as atheists todat simply reject one more mythological god than the Christians whom reject earlier mythological gods like Thor, Zeus, and Isis.







