A recent update on the Carson Beckett front: the controversial Joe Mallozzi announced recently that Carson will not come back as an ascended being and the like. But his return and how it will occur is hinted on or at least there are clues somewhere, in the later half of season 3 of Stargate Atlantis. How true this is remains to be seen but I'm interested to know just how creative the Stargate writers are going to be on this one.
Paul is slated to return for 2 or 3 episodes in Season 4 (we hope).

