I think the most elegant argument against the existence of God is that offered by Mikhail Bakunin: "If God is, man is a slave; now, man can and must be free; then, God does not exist." But most Christians are for some reason comfortable being slaves to an imaginary dictator, even going so far as to admit they are sheep, since nobody but sheep would need a Lord that they call their "shepherd".

We can point out many other inconsistencies in the Christian conception of God. For example, the Christian God is claimed to be omniscient yet also granted us free will. Therefore, God already knows in advance every action I will take. How can I have free will if all my actions are already programmed into the knowledge of God?

God is also claimed to be omnipotent. If I truly have free will, then God does not have the power to override my choices, and therefore is not omnipotent. On the other hand, if he is indeed omnipotent, and chose not to override the choices that led to the Holocaust and 9/11, then he is complicit in these evil acts and thus is not omnibenevolent, and actually must logically be a complete asshole. Furthermore, the acts of the Holocaust were surely AT LEAST as evil as the slavery of the Hebrews by the Egyptians as mentioned in the Bible, yet the Nazis suffered no plagues. It took the power of man, not that of God, to defeat that evil. So why is God indifferent to evil these days? Why did the God of yesteryear care so much about the evils committed against the Jews, and then ignore their pleas and prayers during the Holocaust? Why would a perfect being change his mind about what should be done in response to evil, or change his mind about anything for that matter?

It only makes sense that if God has perfect knowledge, he cannot change his mind about anything since he already knows what is right and what is wrong. If he does not have the power to change his mind, then what good is prayer?

The Christian God supposedly cares whether or not we worship him. As you already mentioned, a perfect being has no wants or desires. Then why does he desire worship from us?

Then there is this argument, offered by Bertrand Russell in Why I Am Not A Christian:
Kant, as I say, invented a new moral argument for the existence of God, and that in varying forms was extremely popular during the nineteenth century. It has all sorts of forms. One form is to say that there would be no right and wrong unless God existed. I am not for the moment concerned with whether there is a difference between right and wrong, or whether there is not: that is another question. The point I am concerned with is that, if you are quite sure there is a difference between right and wrong, then you are then in this situation: is that difference due to God's fiat or is it not? If it is due to God's fiat, then for God himself there is no difference between right and wrong, and it is no longer a significant statement to say that God is good. If you are going to say, as theologians do, that God is good, you must then say that right and wrong have some meaning which is independent of God's fiat, because God's fiats are good and not bad independently of the mere fact that he made them. If you are going to say that, you will then have to say that it is not only through God that right and wrong came into being, but that they are in their essence logically anterior to God. You could, of course, if you liked, say that there was a superior deity who gave orders to the God who made this world, or could take up the line that some of the agnostics ["Gnostics" -- CW] took up -- a line which I often thought was a very plausible one -- that as a matter of fact this world that we know was made by the Devil at a moment when God was not looking. There is a good deal to be said for that, and I am not concerned to refute it.