I swing.
Seriously, I voted for Obama in 2008. I will not in 2012.
I voted Republican in 2008. I will not in 2012. If I thought the GOP had a shot at landsliding the Senate or would have the gumption to eliminate the filibuster, I could hold my nose and vote for Romney to ensure that we get an undivided government that could govern, I would. But I don't see that happening no matter who wins the White House, so neither Romney nor Obama has much chance of getting their domestic policy enacted. That mutes the importance of their differences there as far as I am concerned. Romney has taken positions that would be an absolute disaster for our foreign policy and Obama has proven to be much better on foreign policy these past 3½ years than I thought he would. Probably won't vote Obama either unless none of the third party options meet with my approval. Being better than Romney is not exactly a great reason to vote for Obama, and in any case, no matter who I vote for, South Carolina's 9 electoral votes will be going to Romney.
I sort of feel the same. I guess it's no surprise that our political matrix scores are similar. (Are South Carolinians among those who think that "Texas isn't really the South"? Virginians seem to be arrogant assholes on this point.)
I didn't vote for the GOP in 2008 -- though I considered doing so only to "shoot the bird" at the MSM for its hateful and fraudulent attacks on Sarah Palin. I voted for the Constitution Party.
I have a little different view than you re. the GOP taking the Senate. I've said that if I were convinced that the GOP would win the Senate, then I'd prefer Obama to Romney. Since the SCOTUS decision on ObamaCare, I am now convinced they will take the Senate, so I'm hoping for Obama to win (but I doubt it) and for divided government that can't get anything done.