As somone said above, I don't think anyone knows whether Paps will be a starter or closer in 2007. There's still a lot of baseball left in 2006 and while Paps has been virtually perfect in the 9th, there's no guarantee that will continue. Obviously, if he does falter down the stretch, all bets are off.
My best guesstimate is, though, that if he continues to be lights-out in the 9th, he'll likely be the closer in 2007 and beyond. Paps has said publicly he likes being a closer. Boston is currently trying to "convert" Hansen into a starter.
(Even if this effort fails, Boston might not want to mess with success by moving Paps from the closer role. It's not easy to find a closer who has been as lights-out as Paps, and as good as Hansen is supposed to be, the odds are against him finding immediate success as a closer in the majors. The majority of closers have to toil for a few years in setup.)
What this says to me is that all the pieces are falling into place for Paps to be the closer for the foreseeable future.
I am the Master. Don't question the Master. Just do what he says and be proud.