On point to what Linwood speaks to, there is a dearth of evidence for the existence of (insert supernatural occurance of your choice, i.e. Unicorns, Leprechauns, etc. . . .) and because there is no evidence which favors the existence of such creatures, reasonable adults rarely go into detailed arguments about whether such creatures/phenomena exist.
However, when someone attempts to apply the same standard to the deity popular at any given time/geographic region, we are suddenly shouted down by those who claim that it is illogical to surmise that an absence of evidence is evidence of absence.
Why the differing standard? I think it goes back to Occam's Razor, and to a major cultural bias, and a deep feeling of need in the beleiver to beleive in the deity of their choice, in spite of there being (oftentimes) no more evidence for the god of their choice's existence than there is for the existence of wood nymphs, Santa, Easter Bunny, etc., etc., etc.
While the OP may have made a poor choice of words in naming this thread, his points are still valid. I agree with everyone who says that no evidence for the absence of an Abrahamic God has been presented. Just as there will never be any evidence of the absence of dragons, trolls, hobbits, etc. . . .
This, to me, is an endlessly fascinating subject, and one upon which there are, obviously, more than one school of thought. Beleivers are often going to beleive, in spite of what some will acknowledge is a lack of credible evidence in favor of their beleif. Non-beleivers are going to continue in their athiesm/agnosticism/skepticism, in spite of subjective stories of revelations, miracles, and the like brought to the fore by believers.
I sincerely doubt that this subject is one upon which, at any point in the near future, people on either side of the debate are going to just decide, hey, you guys on the other side have convinced me, and we all end up agreeing. It is in the nature of what we are debating that, barring God deciding to show up in all His glory in the middle of Central Park, we are never going to be able to prove the existence or non-existence of God.
God, if he exists, could make it absolutely known, to every individual on Earth, that He is real, that he cares about you, and that he has a plan for your eternal soul. If the God of the Bible is real and has the attributes ascribed to him by Judeo-Christian scholars, then there is literally nothing, other than His own whim stopping him from showing up and ending all such debates.
To date, He has not chosen to do so. For this, and many other reasons, I, and many others who are like minded are skeptical as to His existence at all. If you imagine that there is no supernatural father figure who is looking out for all of our well-being, then you could imagine a world full of disease, starvation, suffering, war, torture, ethnic/cultural/religious violence, where men are absolutely inhuman to one another. . . . and if one takes a look at this marble we all live on, then that is exactly what one finds.
There are myriads of other reasons I could go in to, and books have literally been written on this subject by a variety of authors, but there are many logical, valid reasons why a person would come to the conclusion that a) we can never know if there is a God - agnosticism or b) there is strong reason to beleive that there is in fact no God - athiesm. None of these reasons, however, are ever going to be "evidence" for the absence of God, as there can never be evidence for any absence of anything.
Think back to Carl Sagan's invisible dragon, which lives in his garage. You can never, ever ever ever provide any evidence that Mr. Sagan's dragon does not exist. You can, however, come to the conclusion, as he did, that a dragon who is unknown, and unknowable, ceases to matter; or you can come to the conclusion that it is not reasonable to expect his invisible dragon exists, as many of us do. And those who come to that conclusion about his invisible dragon, do not come to said conclusion because of any evidence showing the dragon doesn't exist. Instead we come to that conclusion based on the lack of evidence in favor of the proposition that the dragon exists.
B.