This is the second poll I've seen including Nader and Barr that is essentially showing the same thing.
When Obama is matched up head to head with McCain, he's up 6 (close to what other recent polls have been showing).
When Nader & Barr are included, they combine for 7 points (5 of them for Nader) and Obama is ahead by 13 over McCain, which implies that he's getting the vast majority of the Nader and Barr votes. The Nader take from McCain might seem surprising but it makes sense. There are still many disgruntled Clinton supporters that don't want to vote for Obama. At the same time, most probably don't want to vote for McCain. Given a third party alternative (a liberal like Nader for instance), they might feel better voting that way rather than McCain as opposed to the 2-choice scenario.
http://msnbcmedia.msn.com/i/msnbc/se...3_Released.pdf