Audit Trail
I voted in California tonight. It was an electronic machine. In addition to the electronic tally, it makes a print out of your votes as a paper audit trail which each voter checks against the on-screen votes before casting their ballot.
No idea what other States / Counties do.
Also noted tamper evident seals on the IO ports of the machines.
Realize nothing is fool proof, but its not like we are voting using a nintendo here.
Totally understand the concerns regarding fraud however.