Seems to me that given the general biblical illiteracy of the culture we find ourselves in, as well as the general inability of most people to think critically (most thinking seems to be more bumper-sticker or sound-bite polemic), we can't go to the Bible very quickly when we attempt to communicate the gospel to our Post-modern culture and society.
I read a Christian thinker a few years back who suggested that we need to become better Natural theologians rather than better Systematic theologians. What he meant by that is that we should get a better grip on Thomas Aquinas' massive thought-experiment that we now call Natural Theology. Aquinas' experiement went like this: we know Paul says in Romans 1 that everybody knows some pretty basic things about God. So using the evidence we have before us and our own reasoning power, just how far can we get along into our theology without having to rely on Jesus, the Apostles, or scripture? Aquinas got pretty far along, and while others that followed him thought he resorted to a couple of logical cheats to get there (unintentionally), still he made lots of interesting points.
The guy I read said we ought to do a similar, though not as intense thing. Can we converse with a dude in the epicenter of Portland "wierdness" (say on Hawthorne) about the existance - not of God - but of basic good and evil? Can we argue about the sanctity of life - not from Psalms - but from our own feelings towards children and infants? Can we argue about a creator - not from Genesis - but from the amazingly balanced world around us? And then, from there, can we make the move to point them to God, human uniqueness, and creation?
And even to a moral standard? Consider this exchange:
PoMo: "Dude, your metanarratives don't do it for me. I don't need somebody doing their power trip on me; telling me what's right and wrong."
XnDude: "OK, so let me ask you; do you have a sense of right and wrong?"
PoMo: "Sure I do."
XnDude: "Do you, according to your own standards, ever fail those standards?"
PoMo: "Yeah, 'course I do."
XnDude: "Then you -right there - agree with me that you are a 'sinner.'"
The thinker's point (who I mentioned before) was that if our culture denies us the use of scripture, we are not left without authority to speak. God has still given us an ordered world in which he is displayed. We can use that and build upon it to bring the specific good news about Jesus, salvation, and redemption.
What do you think? Would that play in the espresso shop on Hawthorne?