A great legacy of religion on our world
The Bible and Qur'an and their respective religions have inspired the finest works of art and literature. From Shakespeare to the Italian Rennaisance, from the Agia Sophia to the Taj Mahal we've inherited a lot from religion. Continuing excavations around the world reveal beautiful artefacts related to ancient pagan religions too eg. Aztecs and Celts.
Skeptics probably won't disagree with all that.
But can you imagine what art, culture, literature and architecture thre would be without religion?
I don't deny that I enjoyed singing Handel's Messiah in college or that I was awed by the cathedral in Moscow (and expressed amazement that the communists would have torn it down, despite my oposition to the religion the art represented). This is because the artwork has a value and life of its own, independent of the religious ideology it represents. It could just as easily be about the glories of the universe or the trials of life.
One shouldn't think that atheists and other freethinkers are androids or Vulcans. We also appreciate the sublime and expressions of the human spirit. There will always be works of art just as there will always be pursuit of answers to ancient questions. Religion has too long dominated art, community, fellowship and spirituality. We can have these things without the dogma.
There is a minority view out there that says that religion poisons everything that it touches. Whilst this may just be the fighting talk of some atheists, it is evidently not true when you observe art.
And without studying a bit about religion you can't fully appreciate a lot of the best art out there. I'm not suggesting indoctrination, but teaching about world religions benefits our understanding in this respect.
I would say some of the most brilliant music in history (Bach, Beethoven, Mozart, Handel, etc.) would not exist or would at least be drastically different without religion's influence. Religion has definitely has some positive effects, but the negative effects are staggering in comparison. Plus, religion is not required for good music or art. Look at Tool... they're all pantheists. Look at Alex Grey... he's a practicing buddhist/pantheist. Hell, look at John! (his music is available for listening on this site)
"I believe in Spinoza's God who reveals himself in the orderly harmony of what exists, not in a God who concerns himself with the fates and actions of human beings." - Albert Einstein
but I have to wonder if such things could not have come about without any sort of religious influence whatsoever.