Some fine points there, magwitch. In the spirit of spirited debate, a couple of thoughts...
WARNING - SERIES SPOILERS ABOUND!!!
Again, Pullman changes what is in the books. The crucial book here of course is The Last Battle (gee, can you imagine the fuss on all sides if that ever gets made!!!!). In the Narnian world, there is an alternate religion which worships Tash. There is a character, Emeth, who is a devout Tash worshipper and a good man. But in the end, he is given a "buy" - when he says to Aslan he is not a follower of him but one of Tash, Aslan replies "Child, all the service thou hast done for Tash, thou hast done for me".
Now actually this is all dreadfully bad news for the evangelical Christians who are so quick to claim this series for thier own. Evangelicals believe that unless you accept Jesus in this life, you are going to Hell. Lewis' Narnian theology is very different. By analogy, this is saying a good devout Muslim gets into heaven without any Christian conversion at all. It seems to be that it doesn't matter what your faith is or even none, but what is your heart? Then if you have a good heart you will recognise Aslan AFTER death, not necessarily before. So to take the analogy to its logical conclusion, a humanist would be welcome if the humanist ultimately discovered that there was more to life than they'd always believed.
As to the business of "the world is what you make it", this is a perfectly reasonable perspective. Why wait for a Lion that doesn't exist, and even if he did would order everyone about? Pullman seems to enjoy believing in God enough to torture him - his view of God is clearly at odRAB with classic Christian view, or that of Aslan. Having defeated evil witches et al, Aslan's charge to his kings is always "rule with fairness and love", then he leaves them to get on with it. Not much to object to there, really.
Why is Pullman really so angry at a theistic perspective? Because he believes - as fact - that the theists are deluded. Therfore he has turned his views into his own moral crusade. By doing so, I think Pullman has become the very thing he claims to decry. And when he so blatantly changes the facts in the book to support his argument, I get nervous.
I'll tell you why Pullman's rhetoric makes me nervous. His athiesm sounRAB every bit as absolute and dogmatic as that of the religious nutter. Although people are rightly quick to point out all the terrible atrocities and wars waged in the name of religion, there have been many secular conutries in the 20th century with an extreme version of Pullman's ideology, and they were led by people such as Hitler, Stalin and Pol Pot. His views to me genuinely sound more extreme and dangerous than Lewis', who in the end represents a pretty moderate perspective.
Just my penny's worth...