Defining God -- Can it be done?

I will be leading a Bible study using the new Animate curriculum from Sparkhouse Press, the first session of which features Brian McLaren discussing our conceptions of God.  He asks the good question:  When you talk about God, what do you mean by God?  When we have conversations with people concerning the existence or reality of God, we find that the definitions offered by those who deny God's existence don't sync with our own.  So, if that's your definition of God -- well I don't believe in that God either.

As I'm preparing for that conversation, I've also been reading the Miroslav Volf edited book Do We Worship the Same God?: Jews, Christians, and Muslims in Dialogue (a review of which I owe to Englewood Review of Books).  In this book, as with a book I read earlier entitled Do Jews, Christians, and Muslims Worship the Same God?  a group of authors representing these three so-called Abrahamic religions seek to answer the question of what constitutes a proper definition of God, and whether there is any commonality.  The sticking point in the conversation between these three monotheistic religions is the place of the Trinity.  Is it an essential attribute or does the unity of God transcend any understanding of plurality of persons that the apparent divide can be overcome.  The authors in the Volf book are more confident than those in the Neusner, et al, book.

In Brian's discussion of our conceptions of God's nature he turns to the words "apophatic" and "kataphatic."  The first focuses on the human  incapacity to fully define God.  It is, to use the proper translation of the word, a negative theology.  The kataphatic idea suggests that we can speak of God's identity.  The question then becomes -- how much can we know and speak of and how much of the definition of God lies beyond our ability to comprehend and speak.  In the lesson from the Animate curriculum, Brian suggests that we should find a balance between the two.  To choose one over the other will lead us to either affirm too much or too little.  In the conversation with our Jewish and Muslim friends, however, we have to decide how much of our definition to leave off the table.  Can we, as Muslim theologian Reza Shah-Kazemi suggests, priorize God's transcendent unity and find common ground there, even as we may not agree on how the Trinity fits into the definition.  That is, in our conversations do we move toward the kataphatic and insist on Trinity or move toward the apophatic and recognize that God's identity lies beyond our definitions?

So, how do you define God?  What are you willing to live with?  Do you tend toward the apophatic and live with the mystery or toward the kataphatic and seek firm definition?  How do we find balance?  How does our conception of God relate to our conversations with other faith traditions?