[[[[[Florida is the largest of the nation's swing states, and both parties will target it in the November election. A Quinnipiac University Poll released Wednesday showed Clinton would edge presumptive Republican nominee John McCain by 44 percent to 42 percent, if the race were held today. McCain would beat Obama 46 percent to 37 percent, according to the poll.]]]]]

Let's not forget that McCain and Obama had from the start, and to some extent still have, a huge advantage over Obama in name recognition.   (Who had heard of Jimmy Carter back in March of 1976?   Or how well was Bill Clinton known this early in 1992?)   Obama does extremely well when he campaigns in a state, city, or county, and he hasn't done that in Florida yet.
Poll results are notorious for shifting drasticly from week to week depending on the news, etc.    And if the Dems were going to go by early polls like this to pick their nominee, they'd have gotten behind John Edwards back in January, because the most trusted polls were showing Edwards beating ANY Republican and by a wider margin than any of the other Democratics would. Polls also show that right now Hillary Clinton's negatives are higher than her positives - not a good starting point for the general election, especially when Dems probably need a wide margin to keep the election from being stolen in some states.

Not saying polling doesn't give useful info, just that you have to analyze the results carefully in the light of other kinds of info.