In short, if you vote on a Diebold machine, you might as well not bother voting.
Update: Slashdot is also reporting on the security "feature" that allows unauthorized people to change the outcome of an election. Also, in the comments:
In August 2003, Walden O'Dell, chief executive of Diebold, announced that he had been a top fund-raiser for President George W. Bush and had sent a get-out-the-funds letter to Ohio Republicans. In the letters he says he is "committed to helping Ohio deliver its electoral votes to the president next year."Slashdot users are passionate about the subject, as it's already been revisited.
Ken Blackwell (Ohio's Secretary of State (Repub)) and current canidate for Ohio Gov is the one who certifies Ohio's elections, and is the one who approved the use of Diebold's machines.
Ohio State Senator Jeff Jacobson, Republican, asked Blackwell in July, 2003 to disqualify Diebold Election Systems' bid to supply voting machines for the state, after security problems were discovered in its software, but was refused.
When Cuyahoga county's primary was held on May 2, 2006, officials ordered the hand-counting of more than 18,000 paper ballots after Diebold's new optical scan machines produced inconsistent tabulations, leaving several local races in limbo for days and eventually resulting in a reversal of the outcome of one race for state representative. Blackwell ordered an investigation by the Cuyahoga County Board of Elections; Ohio Democrats demanded that Blackwell, who is also the Republican gubernatorial candidate in this election, recuse himself from the investigation due to conflicts of interest, but Blackwell has not done so.