Fine, "in general". There are more mccain states in places where income has gone up, and so on.
Actually, I just graphed it, and correlation is super weak. http://img91.imageshack.us/my.php?image=blahvs9.gif (Stupid Google Docs wouldn't play nice with the graph, so I had to use Excel. Sorry Web 2.0)
Or, if we wanted to avoid simplistic partisan rhetoric, we might say that poor economic conditions tend to cause voters to favor the non-incumbent party.
(In general) Obama does better in states that are doing poorly economically.