Most of the rest of the civilized world does not. Paper ballots, marked in secret, and counted in public seems to work for most democracies. And yet, starting in 1886, the American populace moved to a lever machine. Then, in the civil rights movement, we got optical scanners.
It's more complex, and actually causes more problems than a simple paper and pen system. It was a solution for a problem that never existed, in that the old way of marking ballots was working just fine. So why did we move there?
There is so much chance for chicanery in any system that removes you even one step from your vote. Why do we use machines? They're certainly not any easier. Anecdotal evidence aside, one needs look no further than 2000 to see that.
Here's an article and webpage on the subject. I listened to this reporter talk for about an hour on the subject of voter fraud, and machines, and she competely changed my mind on alot of subjects.
Lynn Landes Discusses Voting Machines
She has many resources on that site that talk about who owns the voting machines, and who stands to profit.
By the by, does anyone know who owns the machines that are counting the Michigan Democratic Internet Primary ballots? Just wondering..