On a related (but more humorous) note, I once saw a SouthPark episode where Cartman froze himself in ice and was awoken several hundred years later, in a world where atheism had replaced all forms of spirituality.
Of course, human beings still warred with one another (because that's what humans do), but instead of fighting over religious issues, countries warred with one another over which "athiest group" had adopted the most scientifically accurate name for itself.
In my opinion, humankind will always need spirituality, and most of the world's ills can be traced to the nature of man, regardless of his religious axioms.