Well, he certainly came with prepared remarks. He did hit the right notes: 1) Obama is more than qualified. 2) Obama has the right temperament to lead as evidenced by the recent financial meltdown (an intellectual curiosity and equanimity versus McCain's chicken-with-its-head-cutoff); 3) McCain's judgment has been further undermined in his pick of Sarah Palin who is a fine woman blah blah blah blah blah, cut the nice crap, but not ready to lead, contrary to what cultists would have you believe. 4) Speaking of crazy right-wing cultists, McCain is running a campaign based on smears while Obama's is more inclusive. The direction of the Republican Party is not good for this country. 5) Tops it off with a demonstration that a person can be a Muslim and die in some pointless war of imperialistic aggression a patriot.
The problem for the McCain campaign is that Powell has credentials. They can't attack the guy. He's a General, a loyal member of the Bush administration, and he sounds calm, rational. This is terrible because his arguments will not only get a lot of publicity, but they're kinda true. He just sounds so reasonable. Not only has he given money to the McCain campaign, but like a lot of undecideds, he's come to his conclusion recently, in light of recent events. He gives people cover to vote Obama. Of course, he also gave people cover to sign on to a stupid, pointless war of imperial aggression, not that the amnesiac American public will remember, or that Republicans can bring it up in their attacks. "You trust Powell? Remember how he totally got the evidence in Iraq all wrong?"
Geez, ya think people are setting up expectations with this "right man for now," "transformational figure in history" stuff? Chances are he will be around average. It's all about hype anyway (look at Reagan especially).