Today's polls released so far show everything from a 47-45% Obama lead (well within the margin of error), with 8% undecided, in the TIPP poll, to a 52-43-5 result in the "Gallup expanded." The CBS and ABC News polls, so far the most favorable to Obama, aren't out for today. So the polls are predicting everything from an Obama blowout to a tossup, perhaps leaning McCain (if, as most observers seem to expect, the undecideds break at least 2-1 in McCain's favor).
Overall, the picture is of a comfortable victory for Obama, but if the pollsters are wrong in their assumptions about turnout (will young people turn out now that the Iraq War has faded from the scene? Will Sarah Palin bring out a higher turnout of conservatives than expected? Will African Americans vote in unprecedented numbers, as expected?) and voter party i.d. (Rasmussen, for example, who has Obama up 51-46, is assuming 39% to 33% favoring the Democrats), it could turn out to be either a huge Obama victory or a close race. One interesting datum: McCain seems to have made serious inroads in Pennsylvania, reducing a double-digit gap of a week ago into the mid-single digits. Very likely too little, too late, but something of a rebuke to the "experts" who claimed that McCain was foolishly wasting resources there.
UPDATE: FWIW, a reader points out that Clinton did three points better in the Pennsylvania primary that the Real Clear Politics average of polls had suggested. Most likely, the undecideds broke overwhelmingly for Clinton.