The Blue Lemur blog has some interesting stuff about the variance in exit polls and actual results in states that use electronic voting machines and those that do not (or those that have them but with paper trails).
Exit polling accurately predicted the results in most states with very little error. Where there were discrepancies, they were significant in the +5 percent range, and always favored Bush.
No paper trails mean no way to contest this. Also interesting is how the AP ‘adjusted’ their exit poll data after they realized they were off by so much. I wonder how past exit poll accuracy compares to this year.
UPDATE (11-09-2004): More details just keep coming: