The national polls are useful, but it’s the individual states that really matter.
Hypothetically, that is the case, but I have heard it said that if a presidential candidate wins the national popular vote by 1% or more, they'll have enough electoral votes.
An example of this principle can be applied to the 2000 election, in which Gore won the popular vote by .5%. If Gore had a 1% advantage in the popular vote, I believe he would have been President.
A win by 4% of the popular vote would be decisive, IMO. But polls out this far are meaningless.
Romney was not my first choice by far, but I think he has run a disciplined primary campaign with minimal stumbling. I think he may surprise his detractors. Although not charismatic, he is no Mr. Nice Guy like GWB or McLame. My take is that he will take the gloves off and street fight and that he will respond immediately to attacks and lies. I think we're about to see someone who will finally stand up to the bullying Obama dishes out and give it back. If he does that, he'll win many to his side who are sick and tired of Republicans rolling over and playing dead. It will be interesting to watch and we'll see soon if I am right or wrong about this.