What time do polls close?

Here's a useful map for those of you who are trying to picture the way the news will roll out on Tuesday night. What places will we hear from first? Where might we see surprisingly early evidence of a Romney blowout, if that's what's about to happen? The earliest sign might come from Virginia, where the polls close at 7 ET. I was imagining Pennsylvania as the possible first sign, but polls don't close there until 8, at which point we'll be seeing Michigan and Missouri. Ohio and North Carolina come in at 7:30, so the impression from Ohio will precede Pennsylvania.