The problem is, one camp believes things on faith - the other on evidence. Those that have only faith will never convinve those who base their worldview on evidence simply because there is no evidence for the claims made by the Christians.
I can completely understand what you're trying to say. However, thinking this through, Christianity and atheism have something in common - both are characterized by certainty. For Christians, it's the certainty that drives the faith. It's the past experience, what we call the 'personal encounters with God' that make us certain that God will 'show up again' today. These perceived encounters are what validate specific scripture passages that speak of His faithfulness. When looking at those statements made by Christians in this thread, there is a consistent proclamation of His faithfulness and His goodness. This is what the believers experience for themselves. Hence they keep claiming that God is good, in response to the questions posed by your fellow atheist friends. These personal encounters become like 'evidence' to us, that God must be real, and that life's pain can be worth it because something good would come out of it somehow. We aren't exactly completely oppositional. The necessity for evidence in the believer's life of God's presence, perhaps experienced in the form of 'blessings', is there, for the believer to be able to conclude that nothing is ever truly in vain. So there is the belief that: Something will be salvaged from a painful experience, and God is moulding me. That, perhaps, in hindsight, God makes it well again, and lives that are wasted, or children that are murdered, might be compensated somehow, because God redeems. Only that perhaps, the atheist would argue from a scientific point of view, that manifestations are purely psychological. This type of view is empirical and fixed in its certainty that truth is and must be measurable, that it must be observable. Religious experiences are therefore purely subjective.So even here, there is a particular certainty that drives the belief in empiricism. I think both camps need some faith to sustain what both sides believe in.
For me personally, I can only say I don't have all the answers. I, too, find my faith puzzling at times. I might even be seen as backslidden by some for being so 'dull' or 'lukewarm', as opposed to being fired up for God and all defensive about Him. But I really don't have the answers. I can't say for sure that I can reconcile a loving Jesus who preached for the cause of the downtrodden with the God of the OT. I think that, however, it is very possible to dialogue with humility and hunger for a greater awareness and appreciation of others' perspectives. It is refreshing to be constantly challenged to think and interrogate my own faith!