As a lawyer might say (OK, I am one), I have no personal knowledge of whether John or Cindy McCain voted for George W. Bush in the 2000 election. However, now that that has been called into question by Arianna Huffington (who says no) and Huffington's truthfulness has in turn been questioned by the McCain campaign (although not yet by the McCains), I can offer the following anecdote as admissible hearsay shedding a little light on the subject:
Over the Fourth of July weekend of 1999, I had the good fortune to accompany my then fiancée (and now happily my wife) to the McCain vacation home in Sedona where she was interviewing them for a Home and Garden Television show. The interview itself was entirely apolitical, focusing on fabrics and furnishing in their lovely Oak Creek abode, topics about which I do recall the senator was less than comfortable discussing.
Always the goods hosts, the McCains also invited us to spend the day with them, including for barbeque, a favorite of John's. And as McCain flipped burgers, I could not help but ask his views about then candidate George W. Bush.
"He's as dumb as a stump," McCain offered. We then went on to discuss other matters (including Vietnam) but that quote remains seared in my memory.
So how the McCains actually voted that November is between them and their voting booth. But if John McCain did end up voting for Bush, then by his own admission he voted for a stump.