Keep Calm and Finish Him
I'm going to propose an idea: in the absence of other evidence, I think we should assume that people who vote on Election Day will be much like the people who vote before Election Day. This election is different from previous ones in one significant way -- we've made it ridiculously easy to vote early or absentee (unless, of course, you're in the military overseas, but that actually is a fairly small population). You don't need to be extra enthusiastic to vote early.
If I'm right, then Republican turnout will turn out (heh) to be quite a bit more enthusiastic, and therefore more likely to vote, than Democratic.
If the population is exactly evenly divided, and 53 Republicans show up to vote for every 45 Democrats, what is the actual result?
53 percent Republican/47 percent Democrats
Now, does all this mean Romney is certain to win? Of course not. Hell, all those D+8 polls could come true. Someone could come up with pictures of Romney in bed with a dead boy and a live girl. A New Madrid earthquake could disrupt the whole country. The Mayans could turn out to have been optimistic.
I'm just saying that the way to bet is that Romney has the odds on his side; instead of letting uncertainty discourage you, there are three days left. Stay calm, do what you've been doing, and remember the goal.