You have to understand that D turnout would be at least as high as in real life while R turnout, even with Rove's machine, would be even worse than in real life.
My guess-
Election Day Job Approval- 32%
George W. Bush/ Richard B. Cheney PV 42.4% 442 EVs
Barack H. Obama/ Joseph R. Biden PV 56.2% 96 EVs
Or perhaps there would be some 3rd Party emergining
Election Day Job Approval- 32%
George W. Bush/ Richard B. Cheney PV 36.4% 460 EVs
Barack H. Obama/ Joseph R. Biden PV 54.9% 78 EVs
Ron Paul/Bob Barr PV 7.1% 0 EVs