Crooked people could alter the totals without a trace...or a trace so vague as to not be readily identifiable and CERTAINLY incapable of reconstructing the original totals.
Paper ballots, read and totaled by machine are the only way to go...hanging chad and all. It allows the contest to be reconstructed manually and allows for statistical sampling of paper ballots as a cross-check of machine totals that could be WAY out of whack.
Electronic voting could be useful if it were done with the current technology for security. Diebold didn't even do something as simple as what every TiVO does, which is use cryptographic keys to verify the validity of the software being loaded onto it. That would have stopped Felten cold.
Just think of how rediculous it is. TiVO, a friggin' entertainment-related company, thinks more about security than Diebold, which is involved in who will run the country.