Gallup's daily tracking poll has Barack up by 8 points. I'd expect about one or two more days of bounce from the convention -- the current polling only goes up to Wednesday, so we don't have any polling after the convention speech. Hurricane Gustav is going to step all over McCain's media narrative, but he'll still get his own bounce out of Palin and some conventioneering.
The more exciting aspect of the poll is in the crosstabs, where Obama's standing with Conservative Democrats climbed by 14 points from Monday to Wednesday. For starters, this reinforces my suspicion that Obama doesn't really have any lingering base problems -- at least no more so than any other Democratic candidate of the last 20 years -- and will probably climb to the low 90s in total support of Democrats. But, second, it suggests to me that the convention was extremely effective at appealing to centrist voters, even as it shored up the base.
This is one of the odd dynamics of the current political landscape. Usually when a candidate needs to reclaim her base, she panders to the extremes of her party. There's some evidence that McCain's Palin pick was just that -- a decision to mollify the evangelical, anti-choice wing of the party, even though he would have preferred a pro-choice hawk like Joe Lieberman or Tom Ridge. Obama has a strategic advantage in that the alienated portion of the Democratic base is actually slightly to his right, meaning that he can simultaneously shore up the base and work on independent and moderate voters. Equally advantageous is the fact that he can accomplish this by attacking McCain vigorously on economic issues. The center of the Democratic party had been grumbling that Obama was placing too much emphasis on foreign policy and not spending enough time on the economy. So, again, Obama really has a lot more maneuvering room here: he can be aggressive and not worry about alienating the center or his base. Very nice.