If impressions mean anything, Obama won the debate last night. He came across as strong, intelligent, and confident, able to look his opponent in the eye. McCain looked petulant, condescending, and personally unable (or unwilling) to look his opponent in the eye.
It was a win on points, not a KO. But it was a clear victory that should give the Obama ticket a shot in the arm. The immediate polls afterward seem to agree with this assessment.