... but let me boil it down to this:
When the details of this encounter fade, as they soon will, I think the debate as a whole will be seen as of a piece with Kennedy-Nixon in 1960, Reagan-Carter in 1980, and Clinton-Bush in 1992.
In each of those cases, a fresh, new candidate (although chronologically older in Reagan's case) had been gathering momentum at a time of general dissatisfaction with the "four more years" option of sticking with the incumbent party. The question was whether the challenger could stand as an equal with the more experienced, tested, and familiar figure. In each of those cases, the challenger passed the test -- not necessarily by "winning" the debate, either on logical points or in immediate audience or polling reactions, but by subtly reassuring doubters on the basic issue of whether he was a plausible occupant of the White House and commander in chief.
I think that's how this debate will be seen. Neither Obama nor McCain made any serious mistakes (except, perhaps, for McCain's churlish on-stage personal bearing); neither had any moments of surprising brilliance or rhetorical flash. McCain performed closer to the top of his debating range than Obama did.
But something similar could be said of the three previous encounters I mentioned. The challengers didn't necessarily "win," but they achieved something significant simply by debating as equals -- especially on national security issues. I think in the long run people will say that this is what happened tonight.