Obama is about to get destroyed if following polling internals, particularly the Partisan trends in Gallup and Rasmussen's larger survey(historically dead on). Along with Independent vote going by 10+ point to Romney.
Long story short, Panthers win
National polls don't matter. Romney hasn't led a single poll in Ohio or PA and if he loses Ohio and PA he simply cannot win the electoral vote.
Romney could very well win the popular vote and still lose.
In regards to Gallup this is the first time they have done a likely voter model in a presidential election so they don't have a track record at all, good bad or otherwise.
Among registered voters in Gallup's poll (what they historically have used) Obama leads by one point.