Polling has got to be the most inexact thing (art? science? seance?) going. There are polls that show Obama ahead by 10 points, and others that show him and McCain essentially even. AP-GfKRoper poll shows them even, as does the George Washington University Battleground poll. Today's RealClearPolitics average of several polls shows Obama ahead by 7.1 percentage points. I guess you believe whichever poll has the results you like.
One thing I do know, none of the polls shows McCain ahead by 10 points, or even 2 points. Certainly outcome-changing events can happen between now and Nov. 4. However, absent something big happening, McCain's last clear chance would seem to rest on the Bradley effect. That is not a good place for him to be, but it could win him the presidency.
Later...since I wrote the comment above, I ran across this Associated Press article that explains how the variance among polls occurs. I found it helpful, maybe you will too.
