Aside from the speech's almost astounding graciousness, note McCain's visceral disgust at the anti-Obama/Biden sentiments in the crowd. Sentiments he knows, on some basic level, that his campaign–especially the Sarah Palin wing of it–whipped up. As I mentioned in my column of this morning, McCain was extremely proud of the way he waged his campaign in 2000, and some important part of him must be flabbergasted that it was Barack Obama taking the comparative high ground this time around. McCain has always seen partisan politics as kind of dirty; to really compete on the presidential level, he convinced himself, he had to hold his nose, at least until the stench became too much to bear.
It's in that context that you should take in McCain's comment about Sarah Palin, that she's a "great campaigner." It played like a compliment to a ravenous Phoenix crowd that loved the Alaska governor much more than their own semi-native son. But coming from a man who chose his concession speech to make a forceful and moving address about race and unity in America, and who will no doubt be doing some serious soul-searching these next few weeks about the conduct of his failed campaign, it was probably more of an insult.