An Outline of Intellectual Rubbish, by Bertrand Russell
This is an absolute classic, including Russell's other essays in 'Why I Am Not A Christian'
 The Genius of Charles Darwin, by Richard Dawkins (video)
This is a fairly new TV series on Channel 4 (UK) that mainly talks about Darwin and his ideas on evolution. The interesting parts come when Dawkins talks to various people about Darwin. So for instance, Dawkins goes into a school and asks 14-15 year old kids what they think of evolution: most, from all faiths apparently, say they think evolution is false because their holy books/church etc told them so. So Dawkins then takes them to some beach where they hunt for and find fossils. He explains geological time and how different fossils get to be in different layers etc and the kids can see them in front of their eyes. Despite even all that evidence, there are some who say that they would rather believe what their church told them than what they see with their own eyes and brains. Fascinating how religion not only provides no evidence, but it also teaches children to disbelieve any evidence that contradicts their faith. Some kids though slowly open up to the idea that maybe evolution is right.
 The Labeling of Children, by Richard Dawkins and Marcus Brigstocke (video)
Some of it funny, this 8-min video talks about the meaningless labeling of children as a Hindu child or a Christian child etc. And about how some of that could be considered child abuse. Dawkins is an evolutionary biologist and Marcus is a British comedian.
 Why I Am Not a Hindu, by Ramendra Nath
Tries the absolutely impossible task of defining a Hindu person, but using Gandhi's definitions and some history, argues why being a Hindu is both irrational and immoral. Its a good attempt, but I think the approach opens itself to several attacks, and also mixes up arguments about whether God exists with moral issues. I have not seen any modern atheist arguments against Hinduism that I would consider a classic.
 Why I Am Not a Muslim, by Ibn Warraq
This book is not available online, though several related articles by Ibn Warraq are available. Ibn Warraq is a pseudonym and his real name is not known publicly - that says quite a bit about freedom and Islam. He wrote his book after the Rushdie affair, which is another atrocious display of religious intolerance and bigotry. (That intolerance though is not unique to Islam, modern Hindutva fanatics are not a whole lot different in their tolerance of criticism). Ibn shows the Koran's texts to be man-made through historical and cultural references, and that of course, brings the whole deck of cards down for Islam. He also talks about how Islam blocks scientific and political progress through mis-education of children.
 Richard Dawkins on the biblical Abrahamic God (Old Testament), from his book The God Delusion
The God of the Old Testament is arguably the most unpleasant character in all fiction: jealous and proud of it; a petty, unjust, unforgiving control-freak; a vindictive, bloodthirsty ethnic cleanser; a misogynistic, homophobic, racist, infanticidal, genocidal, filicidal, pestilential, megalomaniacal, sadomasochistic, capriciously malevolent bully.Says quite a bit about religion and the evolution of morality over the last 1400 years (since advent of Islam). Also see Elizabeth Anderson's If God is Dead, Is Everything Permitted? for more on morality in both the Old and New Testament.