Let's start with the common wisdom of the news media on November 4, 2008:
This is how the election shaped up that night before any polls closed:
At 6PM EST on November 4, 2008, the situation so showed:
123 electoral votes seemed likely to go to McCain under any circumstances as shown by polls and the behavior of candidates. Those are in the darker shade of blue shown on the map, and they indicate the states likely to be called as soon as the polls close statewide.
37 electoral votes (in pale blue) had a preponderance of chance of going to McCain; they would if nothing really strange happened. They might get close, but they showed no strong indication of going to Obama.
115 electoral votes (in pale green) are shown as swing states and districts -- states or districts that could all go one way or another. If any of them could be called early, then something was fishy about the models for predicting elections. These all include all states that no Democrat had won since 1996, but were up for grabs.
37 electoral votes (in pale red) are shown for states that had split in 1992 and 1996 for Dubya, and Pennsylvania, where McCain made a last-hour blitz of a campaign, were purportedly not likely to be called early -- but Obama was likely to win them.
227 electoral votes in dark red are known to come from states that few think have any possibility of being called for McCain.
The rest, in green, could supposedly have gone either way -- all 105 of them.
McCain was a sure winner, or so it seemed, of 123 electoral votes with another 37 having very slight questions that could be answered quickly and thus a near certainty of 160 electoral votes. Obama was seen as a sure winner of 227 electoral votes with 37 likely to be called for him with questions that would be answered fairly quickly and thus seemed very certain to win 264 electoral votes. 270, of course, wins. McCain could conceivably lose Montana and NE-02 and still win... but that was it. Nevada would have made a tie to be determined in the House of Representatives where the Democrats were going to go for Obama.
Of the states in green, Indiana was one of the first to close its polls (statewide at 6PM local time, 7PM EST statewide), and it was seen to be almost evenly split. If McCain lost Indiana he would lose the election because of 264 other electoral votes reasonably certain to go to Obama. Of course if the news media could call Indiana quickly for McCain, then McCain's chances in some other swing states suddenly became much better because some of the other states have obvious similarities of demographics and political behavior to Indiana.
At 7PM EST the media could make quick calls on two states: Vermont (Obama) and Kentucky (McCain). No surprise there. Instead of darkening them I am going to show them in very pale colors as if lighted for contrast:
At 7:30 PM, West Virginia was an instant call for McCain, South Carolina could be called before an hour was up, and a bunch of states could be called quickly at 8PM EST:
The rest were still open or were counting but uncalled. There were no great surprises.
Polls had closed in Indiana, but the voting was unusually close -- in a state that last voted for the Democratic nominee for President in 1964. They had also closed in Virginia, Ohio, and Florida somewhat later but were still too close to call -- as they would remain.
Pennsylvania was the site of a last-hour campaign blitz by McCain, as was New Hampshire. Those gambles apparently didn't pay off.
Arkansas closed its polls at 8:30 EST, and by 9PM Alabama and Pennsylvania would be called. In any event another group of states were instant calls at 9PM: KS, TX, NY, MI, MN, WI, RI, WY, and a bunch of states that didn't get instant calls. When Pennsylvania was called for Obama, then a McCain victory depended upon everything else going right.
Nothing in green had changed colors, so although McCain still had a chance to win, if a poor one, nobody could write off the 2008 election yet. That would soon change: Georgia, Mississippi, Louisiana, New Mexico, and Ohio would be called.
Obama won Ohio, a state that McCain absolutely could not afford to lose, as the number of outstanding votes approached the difference between McCain and Obama. Ohio was expected to be close, and it would be, but for McCain it was on the wrong side. At this point Obama had 205 electoral votes sowed up, and even if he didn't win Iowa but won the West Coast other than Alaska, he would pass 270 electoral votes no matter what happened in any of the states still colored green -- swing states still too close to call or still open. Obama, all knew, would win California, Washington, Oregon, and Hawaii and their 77 electoral votes.
The next hour or so would be almost anti-climactic, with Obama winning Iowa instantly and McCain getting Utah, North Dakota, South Dakota, and four of five electoral votes of Nebraska. At 11 PM EST any suspense about who would win the election came to a swift end:
Idaho would go for McCain, but we all know where the great population centers of the Pacific Coast went:
... Virginia, Indiana, North Carolina, Florida, Missouri, Montana, Colorado, Nevada, and NE-02 were yet to be called. Arizona hadn't been called yet, either. Alaska was not yet closed. Of the states that McCain absolutely had to win, he had lost only one -- but as this election would prove, one would be enough.