I propose equal time - present every creation story ever written.
Give students the the facts then they can compare these to the theories and stories - relious and fact based - so can make up their own minds.
I agree with you that creationism should be should be taught, in its various forms, as religious mythology and not science. The reason for this is because so much of our literature, fictional and metaphysical, is based on various creation myths from ancient Babylon to the bible.
Additionally, it is difficult to completely understand the socio-economic and political events that have shaped our history without some knowledge of religion.
So yeah, throw a bone to Judeo-Christian mythology, but include the others as well. The first thing any inquisitive young mind will do when presented with fifty slightly different versions of the same story will be to ask: why are all these stories the same, I thought the bible was unique?
At that point the light bulb goes on - and stays on unless the kid gets a hold of some Chick Tracts.