Barack Obama has a slight lead over John McCain, 47-45, in Mason-Dixon Research & Associates latest Florida poll, conducted for NBC's Today show. That means the race is basically dead-even, considering the error margin of 4 percent.

Voters prefer Obama by a slight margin to handle the economy (49-44) and to reform government (48-44). But McCain trounces Obama on the question of who's best to handle national security: 57-39. Military voters favor McCain 57-39, those who haven't served prefer Obama 49-42.

Also keeping McCain strong: white support (he edges Obama 50-42) and support among Hispanics (49-43), a crucial swing-voting demographic.

Obama has a decisive lead among black voters (88-5) and leads among women, 49-41. Past election exit polls show that a candidate who captures 45 percent or more of the woman vote generally wins the state.

The biggest swing in the poll: name-recognition for Republican VP pick Sarah Palin. About 75 percent of voters didn't recognize her name in the last Mason-Dixon poll in August. Now, only 2 percent don't recognize her. About 45 percent of voters view her favorably and 31 percent unfavorably. That compares to Joe Biden's fav/unfav of 39-21.

Palin has also had a bigger effect on her ticket than Biden has on his. About 60 percent of voters say Biden's pick had no effect on their vote, compared to 37 percent for Palin. And 36 percent say they're more likely to vote for McCain because of Palin, while 23 percent say it made them less likely. Biden's more likely/less likely numbers: 21-15

The results came on the same day that Quinnipiac University announced polling results showing Obama ahead in four other crucial battleground states, Colorado, Michigan, Minnesota and Wisconsin.