So for this week's general election, we used Diebold's optical-scan system instead. Here's side 1 of my ballot, and here is the precint's ballot box and counting machine.
I'm now absolutely convinced that this optical scan scheme is the way to go. The procedure is very simple. They hand you the paper ballot, a secrecy folder, and a felt-tip pen. The ballot is made of heavy paper stock, so the ink doesn't soak through. As you can see in the photo (check the full-res version if you need to,) the page layout makes it clear what circle to fill in for what candidate (or what's "yes" and what's "no" for the propositions.) When you're done, you slip the ballot into the secrecy folder, so nobody can see what you filled in. An inch of the ballot (with nothing printed on it) sticks out the end of the folder. The ballot box has a machine attached and sealed to the top of it. You insert the folder into the machine, which pulls the ballot out the end of it. The ballot is scanned and validated. If you overvoted for an office (voted for two candidates when you should've only voted for one) it throws an error message on its LCD screen, beeps, and spits the ballot back out. No hanging chads, no guessing at intent later, and you get a chance to fix your vote instead of having it discarded. If the ballot is unreadable, or you draw stuff on it, the machine can catch that too. The errors are caught while the voter is still there to fix things. If the ballot validates, it's dropped into the box. The LCD shows the total number of ballots it has counted, but does not show any results. I'm certain that the machine is counting as it reads ballots, so at the end of the day, there's no need to pull the ballots out and feed them through again. (This is how punch card balloting works in Illinois--the ballots are counted at the precint by the election judges, and counting machine spits out a paper tape of the results, which get carried or phoned into county HQ.)
What wins me over is the simplicity. The "user interface" for the voter is simple and familiar. A sheet of paper with some boxes you fill in. Touchscreens can develop accuracy problems. Anyone with a Palm Pilot or PocketPC can tell you how they've often had to recalibrate their screens, when you touch one place but the machine thinks you touched another place. Touchscreens also have problems with dirt and grime, which you'll have problems with especially in hot or dusty climates. Both of these can make it hard for the voter to vote for who they want. The counting mechanism has an audit trail, with no added effort required. They save your paper ballots in the box underneath the count machine. If the machine breaks or is suspect, they can pull 'em out and recount with another machine, or by hand.
The counting machine is a simpler piece of hardware. There's no need for the complicated UI an interactive touchscreen computer requires. True, the touchscreens make it easier to support multiple languages. But, I don't think that's a big enough win to justify them. We've gotten good at making alternate-language paper ballots available in places we need them. (Never mind, I'm a firm believer in immigrants LEARNING TO SPEAK FUCKING ENGLISH.) There's also just one piece of hardware for the whole precint! Instead of a dozen complicated machines for a dozen booths, there's one simpler machine, no matter how many booths you set up. Fewer points of failure--particularly from a power perspective. Touchscreen computers are expensive, and more expensive still when you add paper verification receipt printers (and receipt boxes) to them, and uninterruptible backup power supplies. (Those battery backups probably aren't reliable, either, given how infrequently they are charged and cycled.)
Touchscreens are attractive from an "ooh shiny!" and a multi-language perspective, but they are a liability in every other way. Of those two perspectives, one is meaningless and the other is manageable. To hell with 'em. We'll forever be expending energy to maintain them and oversee that they're not hacked or tampered with at the factory. With optically-scanned paper ballots, it's easier to catch problems and fraud, which is a strong disincentive to try that.