Who is the greatest NFL QB of all time?

I would have to vote for either Johnny Unitas or Bart Starr. Starr only lost one playoff game, and was the first three-peater QB (1965,66 and 67). Those Packer teams from the 1960's won 5 championships and the first two Super Bowls. True, they had the Lombardi sweep, but Starr was a masterful field general who got the job done (He was a lousy head coach, though).