If that's how it went, then (assuming my math is correct), if the Democrats won Iowa and everything to its left, and the GOP won CO and everything to its right, then it would be a 269-269 tie. And so I guess CO and IA would collectively be the "Ohio" of 2008, with the election being most likely to swing on the outcome of those two states.
I win.
Wow, extremely good call 2 years in advance. Congrats.
It was indeed Colorado and Iowa, with Obama needing Colorado for an outright victory, and McCain needing Iowa. However, assuming Obama would've won in the Democratic-majority House in the event of the 269-269 tie, the true bellwhether state of 2008 was Iowa.