McCain just had to show that his experience mattered. He was successful in doing so. Going into this debate, undecideds likely wondered: Is Obama's experience an issue? Is McCain too old? Who will have a sensible foreign policy? What about domestic policy/economics?
First question, yes, it was, especially now that Kissinger basically stated the Obama has mischaracterized his views.
Second question, McCain seemed deft, quick-thinking, and wise. You know, like how we should probably look at older people. He turned age into an asset tonight.
Third question, McCain by a wash -- Obama suggested an aggressive-ish foreign policy and echoed McCain on a surprising number of issues. But, rhetorically speaking, it's hard for anyone to argue with someone who thinks anything short of victory is defeat. You have to come up with a number of thoughtful arguments that convinces that the optimal case is a pullout. Obama's "We'll save money, though!" point fell completely flat.
Fourth question, Obama and McCain neck and neck. In this area I'm probably alone to suggest that I think McCain was very strong here. With a nervous start, he suddenly sprung to life and started hitting Obama on his own record. Obama said he rescinded his earmarks. McCain said, "Only when he started his presidential campaign did he do that." Somebody. Did. His. Homework.
As for whether the Wall Street rant didn't go over well. Who knows how it went over? Whatever he addressed, he seemed to do so with authority, particularly on tax cuts, business tax cuts, etc. I only wish that when Obama said, "You're giving corporation billions," etc., McCain would have responded, "When you tax companies, they cut jobs. If you allow them to keep their money, they do more with it. How does economics work in Chicago?"
Speaking to other DC-right-wingers, many looked a little upset about how McCain had thrown the most-productive under the bus. I just don't think doing so hurt him.