What time do the polls on the Left Coast close? Probably somewhere around 9 or so EST. Once that happens, it’ll be the downhill run. As for when the election can be declared, that’ll be when someone picks up enough votes to have 271 EVs. Judging by the map on 538, I’d say that the election will probably be decided before it gets to the West Coast (but only just barely). If its a nailbiter, it’ll go until the wee hours of the morning.
Ah well, Over Here[sup]hehehe[/sup], we have paper ballots and they all have to be counted after the polls close. So we have Peter Snow and his Swingometer. Great fun, actually - even if the last election was the first one for which I stayed up despite being a foregone conclusion.
Nate will be on Dan Rather’s online show
Sweet! I can hear Dan now, “This election has gone down into the basement dungeon, put on a leather teddy, some ‘fuck me’ pumps and is standing with one hand on its hips asking us, ‘Are you man enough to handle something like this?’” 
Neat map of closing times here.
As for calling the election, well, they won’t have any choice if it’s a landslide. Calling states while there’s still voting going on is another kettle of monkeyfish.
If Obama can take Virginia, North Carolina, Florida, and Indiana, then he can have 270 electoral votes before the polls even close west of the Mississippi River. Naturally they’ll still prefer to wait until the polls on the West Coast close first (though for some reason they’re never arsed about Alaska and Hawaii).
It may not get to that. If it looks like a blowout, McCain may concede before that point.