If he didn't say that, then we could see a number of major differences happen with this little butterfly. I'm going to operate under the assumption that all the primary candidates are the same.
Lets say that this has an effect on down ballot elections across the country. Firstly, in Georgia Obama lost by maybe 5 or so points and Jim Martin, the Democratic Senate candidate, lost by 3 points. Without this in the news cycle, it could have the ramification of giving Martin the edge to win the state, even if Obama still doesn't win the state.
Franken could have won by a larger margin and been able to be seated as soon as the new Senate started.
A reach possibility would be the Senate race in Kentucky, where Bruce Lunsford lost by six points against Senate Majority Leader Mitch McConnell. It'd be more of an outcome of the chaos effect than the direct workings of Obama having never said that comment that would lead to Lunsford unseating McConnell, but the ramifications would be enormous. McConnell was the one who said that Senate Republicans' first priority is to make Obama a one-term President. His talent in whipping votes and obstructing on a massive scale has basically shaped the Senate for the last 10+ years and if he were gone, then really anything could happen.
Another thing to note is that Obama could have won in places like Missouri and Montana (which McCain won by close margins) if he is perceived all that differently by rural voters. This would boost his Electoral College win by 14, giving him 379 and tying him with Clinton in '96 as the 28th largest win ever, but I think it'd have a bigger impact in how he's perceived, and give him bigger political capital in a symbolic sense. Missouri is seen as one of the most severely racist states outside of the Deep South, and Montana is often pejoratively viewed as rural and hick-ish. Him winning there could have a monumental effect on his presidency even if it means very little in electoral terms.
In the House, giving a generic +2 point boost to all Democrats and a slight loss to Republicans when that could play a factor (which would be considerable, but just for fun) the following races would shift or be too close to call:
CA 4
CA 44
LA 2
LA 4
MN 6 (goodbye Michelle Bachmann)
MO 9
PA 6
SC 1
VA 2
WA 8
Assuming half of these go to Democrats, that'd be plus 5, bringing their House victory margin to 26 and giving them a little more breathing room.
If this all also butterflies the Tea Party Movement, or at least kneecaps it, you probably wouldn't see 60+ House seats and 6 Senate seats go over to the Republicans in 2010. They could end up limited to maybe 20-30 more House seats (comparable to what the Democratic Party had gained in each of the previous elections) and flip 3 Senate seats (Arkansas, North Dakota, and Indiana seemed pretty likely to flip).
This would spiral into an unrecognizable Obama Administration. Interesting stuff.