Disclaimer, I'm an Obama supporter, but the point I'm about to make here on how to aggregate polls is not, to my knowledge, beneficial to one candidate over the other.
Jerome makes a point to talk about how his EV calculators rely on the most recent polls for each state. I've got a couple of quick graphs on the flip that will demonstrate how this isn't a very reliable way of looking at state-level support.
First, remember how the benefits are calculated. Social Security basically looks at our lifetime Social Security contributions, adjusts it for average wage growth, and constructs a monthly benefit for us. That's vastly simplified, but good enough for the purposes of this discussion.

Electoral-vote currently reports them by the day the poll was released, which doesn't show a clear picture of how the nation is feeling every day since the poll dates are scrambled.
But, when I went through each of the last sixty days and counted up the EVs by how the polls were being answered each of those days, averaging multiple polls per state if necessary, I came up with the following graph:
· SD: New Poll Shows Tim Johnson Romping (lowkell)
· Iowa commission takes one small step against CAFOs (desmoinesdem)
· LA-06: Cazayoux's Gittin' It Done! (DailyKingFish)
· Secrets of the American Future Fund (chase martyn)
· Happy Birthday Jerome! (Jonathan Singer)
· Oilmen For Scott Garrett (NJ-5) (Aaron Banks)
· Youth Delegates at DNC Outnumber RNC 15 - 1 (Mike Connery)
· LA-02: James Carter's First Ad (DailyKingFish)
· Clean Coal's Goodie Bag for Dem. Delegates (lowkell)
· Liveblogging Obama Town Hall (fbihop)
· McCain's Goons Throw Birthday Cake In Trash (fbihop)
· IA-04: Would-be independent candidate fails to qualify for ballot (desmoinesdem)