Considering that whoever is elected will only be able to implement a small portion of the campaign promises, I try to evaluate on believability and leadership. Each candidate won some rounds, but I gave the belt to McCain; not a knockout or TKO, but a narrow, split decision.
However, if the election were today (or if I was voting early, before all four debates) I would have to vote for Obama. He needs to develop more, but he seems acceptable. I continue to have serious concerns about McCain's age, combined with his apparent weak choice of a running mate. Had he chosen another, stronger partner, it would at least be a toss-up.
Check back after the VP debate, and this opinion may change.