One mistake that I believe several people here are making (and part of the reason that threads like this seem always to devolve into spite and vitriol) is that there is a vast difference between what one can know and what one can prove.
Knowing comes from absolute faith in an idea; it is the absence of doubt. But simply knowing something is not sufficient to prove it to someone else.
Josh McDowell's treatise is compelling (I attended one of his seminars when he visited Virginia Tech back in '91 or '92), but ultimately (in my opinion), all it proves is that the Bible is a consistent document. It doesn't prove that the spiritual things beyond the ken of man that the Bible speaks about are true, because such things cannot be proven; it merely proves that the document itself is an accurate record of certain events.
Scenario (A real stretch, and not something I profess, but it makes a point): Could an all-powerful God, capable of creating the Universe, not arrange the historical things that happened in the bible, for purposes entirely other than what are stated in the Bible? (I'm not asking whether He did. I'm asking whether He could.) And the answer, if you think about it honestly is: yes. The veracity of the Bible's account of historical events, even if it is unequivocally true, cannot speak with certainty about the motives of God. So as compelling as McDowell's evidence is, it proves nothing of the actual Mind of God.
There are things that I know, without a shadow of doubt in my mind, are true. Some of these things are in conflict with things that others here (perhaps Christians, for instance) know with equal certainty. Is there any point for me to argue with them to try to "prove" these things? No, there is not, because "knowing" and "proving" are entirely separate things. Likewise it's pointless for them to try to "prove" the things they know to me?
Everyone here knows something. No one here is going to prove any of that to others who know something different.
In the interest of civility, I suggest we back down from arguing over which path to reach the Divine is the right one. We are all on our own path for our own reasons, and that should be enough for everyone else.
-BP