I can't believe I didn't get (until it was stated flat out) who Shadow really is/represents. Thinking back on it, American Gods was full of clues to his identity, for someone who knows the stories. And I do know the stories, I always have. I was practically raised on the myths and legends of any culture you care to name.
So quite how I managed to miss that is beyond me. Must have been having a bad-memory day.
Warning: the comments to this post contain spoilers.