That is the final nail in John McCain's coffin for sure. Powell has had a favorable rating between 60% and 70% thorughout the entire election season and in mock contests Between both Hillary and Obama. Undoubtedlty his opinion will have a huge sway.
One does have to wonder if Powell is eying a cabinet spot. I would hope that Obama would offer such and Powell would accept because that would be a good thing.
I understand many believe that no one could vote for McCain without being a racist, but while I could never vote for Obama for the many reasons I have stated, I would have voted for Powell in a second.