First of all, we're so far into this downturn that nobody is going to blame it on the next president. Clinton didn't get blamed for the recession that he inherited from GHWB's term (although he got the credit for pulling out of a recession that arguably we were through with by the time he took office). Similar dynamics will probably be at play here.
Second, I think Obama-McCain is going to look a lot more like Clinton-Dole in terms of the outcome. The MSM likes to find polls where they're neck and neck because they like a horserace. I expect this one is going to be a blowout, however. A lot of republicans don't really like McCain and he's not a very appealing candidate to anyone.
Third, the whole counter-reaction to Obama and/or rioting is probably overdone. Yeah, if its close and Obama loses to a supreme court decision, you'll probably see some pissed off folks who have more melanin than others. The country will still go on. And wrt neo-nazism, when you look at Clinton there was a whole strengthening of the UN-black-helicopter crowd which ultimately seemed to lead to the Oklahoma bombing. If Obama gets 2 terms there might be a similar kind of domestic terrorism incident, but the backlash from that should self-limit any neo-nazi / militia strengthening. We're not going to wind up looking like pre-WWII Germany.