This is McCain interviewing Walter Isaacson at the Aspen Institute: "I have not missed any crucial vote."

Says Satyam at ThinkProgress:

McCain’s has actually missed several "crucial" energy votes. In July alone, he missed every single energy vote brought to the floor. This session, McCain has skipped votes supporting renewable energy tax credits four times, all of which were filibustered. In June, for example, McCain missed a vote on the landmark Lieberman-Warner climate change legislation.

McCain has also been the "crucial" absent vote on key legislation. In December, legislation stripping tax break giveaways to Big Oil and investing in cleaner sources failed by one vote, 59-40 (Vote #425); McCain missed that vote to campaign. In February, McCain skipped a vote on extending tax credits to renewables, which also failed by one vote (Vote #8). Both times, McCain was the only senator absent.

Or rather: What Joe said.