Is it possible to be a Christian and not be a Theist? This is one of the critical questions facing Christianity in the 21st century. Of course it's roots are deep within the last century and trace back to at least the Enlightenment.
Paul Van Buren's 1963 book "The Secular Meaning of the Gospel" is a good example of one of the first forays into this kind of thinking. Probably the best known contemporary proponent would be Don Cupitt, whose books include "Taking Leave of God". New Zealander Lloyd Geering also makes a stand in this vein in "Christianity Without God". At first the idea seems non-sensical, but it arises from some of the best theological minds of recent times including Paul Tillich who described God beyond personal terms as the ground of all being. Bishop John A.T. Robinson popularised some of this thinking and in doing so divided the church of the 1960's.
There are actually 2 distinct streams of thought. The first group find the concept of God now to be irredeemable, though they may retain respect for the teachings of Jesus. Those in this category typically see Christianity on its last legs, perhaps offering some general moral direction to the community but on the whole we are left with a rather pale imitation of religious faith.
The second group affirm a real God experience but are discarding the projection of human attributes onto the character of God (anthropomorphism). In simple terms, God exists but should not be understood as the big, white bearded guy in the sky. This kind of thinking challenges some biblical images, such as the angry or jealous God, which may be welcomed. However, it also calls into question the incarnation of Jesus as the decisive manifestation of God. If we can't project our humanity onto God, can we really project God's divinity onto a human being?
Can we have a personal God without making God into a person? Doesn't this ultimately go against the commandment against making divine images? None of these questions have easy answers but they are worthy of some honest thought, discussion and perhaps even debate.