As per this WaPo article,
more than 80 percent of voters will use
electronic voting machines in the Nov 7 election, with a third of all
precincts using the technology for the first time.  The massive switch
to e-voting machines was initiated by the Help America Vote Act,
supposedly in order to prevent the sort of problems plaguing the 2000
Florida recount debacle, involving hanging chads and the like.  But
such systems are prone to new and horrible technical difficulties, of
the sort characterizing last week’s "debacle" in Maryland (see here for details).

By now it has also been multiply established that these systems contain serious security flaws (see also this article and this report).  This first-person account of a hacking of a Diebold system really brings it home:

So,
TJ became convinced that it was all right to upload the memory card,
which he did.  And there, on the central tabulator screen, appeared the
altered results: Seven "Yes" votes and one "No" vote, with absolutely
no evidence that anything had been altered. It was a powerful moment
and, I will admit, it had the unexpected result for me personally of
causing me to break down and cry. Why did I cry? It was the last
thing I thought I would do, but it happened for so many reasons. I
cried because it was so clear that Diebold had been lying. I cried
because there was proof, before my very eyes, that these machines were
every bit as bad as we all had feared. I cried because we have been so
unjustly attacked as "conspiracy theorists" and "technophobes" when
Diebold knew full well that its voting system could alter election
results. More than that, that Diebold planned to have a voting system that could alter results. And I cried because
it suddenly hit me, like a Mack truck, that this was proof positive that our democracy is and has been,
as we have all feared, truly at the mercy of unscrupulous vendors who
are producing electronic voting machines that can change election
results without detection.

Why not use the voting procedure used in Canada?  Besides making elections too hard to manipulate, such a simple system wouldn’t involve yet another massive transfer of taxpayer money to U.S. corporations.