This was originally posted as a comment to a different thread elsewhere, but I put a lot of thought into it, and I thought it was worth more than a comment.
I've lived in the Panhandle my whole life and it's not nearly as red as people seem to think. The majority in those counties are conservative, but they all have sizeable minority populations and progressive subcultures. He'll certainly win (and win big) in Leon, Gadsden and Jefferson (might win Wakulla as well) and could get as high as 40% in much of the rest of the Panhandle.
As for the rest of the state, there is a pretty significant Democratic voter registration advantage. Obama will win 80-90% of those Dems, the majority of independents, and 5-10% of Republicans. And keep in mind you'll see probably a 10-15% in black voter turnout and you might see a slight bump in Hispanic turnout -- and keep in mind Cubans are no longer the majority of Hispanics in Florida and Republicans are losing ground swiftly amongst Cubans anyway.
Here's how I think Obama wins Florida:
95%+ plus of black vote
65% of female vote
60-70% of non-Cuban Hispanic vote
40-60% of Cuban vote
60-70% of urban professional vote
90%+ of environmental vote
5-10% of Republican vote
40-60% of working class vote
60-70% of youth vote
5-10% of religious conservative vote
55-65% of independents
And keep in mind, all of the pro-Obama constituencies will have increased turnout (some of them significantly so, such as African-Americans and youth), while most of the anti-Obama constituencies will have decreased turnout. This invalidates any of the current models that are being used to predict the vote.
That being said, there is little evidence that Obama has much problem with white working class voters. Those arguments are largely based on Obama's matchup with Clinton. But he won't be facing Clinton in the general, he'll be facing McCain. And Obama and Clinton have a basically identical voting record on issues important to working class voters. McCain has a horrible track record. Obama will do fine with this group, even though he doesn't particularly need to.