I think you can only see atheism as a denial if you are starting from a position of faith. And that's really the problem isn't it? As an atheist I have no faith (which is why I am an atheist) I do not feel the need for faith, and think it is either something you have, or you don't. I enjoy having intellectual conversations about religion, and find religion (from a historical, political and cultural study point of view) fascinating. But that's it. I can't really have a conversation about belief with someone of religious conviction, because we have no common ground. I was brought up a Catholic, and would describe myself as culturally Catholic/Christian, because I am very aware that my moral system is deeply embedded in Christian traditions. I have a good knowledge of different faiths (although most in depth for Christianity, I also studied Islam at university). My big sister is a vicar, and I am always aware of that line we can't cross in conversations because of my atheism (I am sure she thinks I will be "re-saved" at some point).
On Narnia, I'm not sure. Loved it as a child, and read all of the books many times. Found the Last Battle disturbing once I started studying other religions, because their seemed to be the assumption that followers of Tash (and I kind of thought this just might be Islam) would go to heaven if they were really good, and this seemed to me to say not that Aslan was a universal God, but that he was the only god (just happy to acquire "good" people who had been a bit deluded).
I reread The Lion the Witch and the Wardrobe fairly recently, and was shocked at how sexist it was, and thought that I would be deeply uncomfortable reading it to my children. I will be interesting to see how the film is reviewed, as ds is interested in seeing it (although this is because he liked the battle scenes in the trailer, and thought it was an adventure film)