I'm sorry if we're not allowed to post a vid in a debate thread like this, but I think this particular vid fits in quite well with the current discussion.
Just read Rrhain's message a couple posts that started with "what weighs more, a ton of feathers or..." for a summary of this vid. Basically, the vid talks about the calculations regarding the rediculously high atmospheric pressure we would have if we have a canopy above the atmosphere pressing down on us and the energy that would vaporize us all when all that water comes down.