I have spent a lot of time thinking about what Jesus means when he uses the language "Kingdom of God" and "Kingdom of Heaven." I think that they mean the same thing, and I don't think Jesus is referring to a place where we go when we die.
I am reading my way through N.T. Wright's works on the Gospels, and I'm currently on Mark for Everyone. In his commentary on Mark 1: 9-13, Wright says, "Heaven in the Bible often means God's dimension behind ordinary reality" (p. 5). He elaborates, "It's more like an invisible curtain, right in front of us, was suddenly pulled back, so that instead of trees and flowers and buildings, or in Jesus' case the river, the sandy desert, and the crowds, we are standing in the presence of a different reality altogether." (p. 5).
And then, of course, we have to live in the tension of knowing about the different reality while living in the ordinary reality too, with people who have never seen the alternate reality. The gospels are written partly to tell us how to live in this tension.
May we see behind the curtain, today and every day--and then, may we find a way to live into that totality.