Most likely when the exit polls and the first hours results are in from Florida the election result will be clear.The extra hour is required so the mistake the networks made declaring that Kerry had won Florida based on the exit polls would not be repeated.
If Florida goes for the President Obama there appears to be little, if any chance for the GOP to gain the 270 electoral college votes required to win as this map shows, and that is even allowing for Colorado/Ohio/Virginia/Iowa/Indiana/North Carolina to be won back.
The only remote outside possibility for the GOP might be if Santorum was the nominee and won Pennsylvania. Simply, if Florida is lost for the GOP then Republicans might as well turn off the TV around 9 p.m. as far as the presidential result is concerned. Obama could even lose New Mexico, Nevada and New Hampshire and still win
President Obama can win with Ohio even with the loss of Florida/Colorado/Virginia/Iowa/Indiana/North Carolina/Iowa/ and even volatile New Hampshire
President Obama can win with North Carolina even with the loss of Florida/Colorado/Virginia/Iowa/Indiana/Iowa/ and the one EC vote he gained in Nebraska
The challenge for the GOP is such that even if they win Florida, just the loss of Virginia, which went strongly for Obama in 2008, will mean the election is over.
The challenge for the GOP is indeed striking, as can be seen by this map. Florida/North Carolina/Virginia/Ohio/Indiana have to be won back as well as either Colorado or Iowa