Election administrators are slowly abandoning the touch screen voting machines that were widely adopted in the wake of the disastrous butterfly ballot of the Florida 2000 election. These machines didn't produce a physical ballot, so voters had no way to know if their vote was tallied accurately once it went into the machine.
One controversial new idea to use machines that still use a touchscreen to capture the voter's intent, but print a paper ballot. The catch is that ballot would contain both real letters that the voter could read to verify their vote was recorded correctly, and a bar code that only a machine would read to record the actual vote. Voters would have no way of knowing, however, if the bar code correctly corresponded to the writing on the ballot.
Touchscreens have an advantage in that they can display ballots in multiple languages and are more accessible for some disabled people. Hand marked ballots avoid potential errors in machine programming or printing, but are potentially harder to tabulate by machine.
One option would be to require all ballots, whether hand marked or machine marked, to be audited so that any errors (or hacks) in the tabulation process could be caught.