I must admit, I was a bit iffy about (SPOILER! highlight to see) [Rex also staying immortal, as a result of him getting Jack's blood] but apart from that, I thought it ended alright. I mean, it was kinda obvious that they were going to have to give Jack back his immortality from the beginning, but yeah...
Speaking of which, I just realized something. We see the Face of Boe die in series 3 of Doctor Who, in the second or third episode, and in the finale of that series, it's pretty much revealed (or at least hinted at) that Jack IS the Face of Boe, or should I say, the Face of Boe is just a really old Jack. But if Jack's not able to stay dead, then surely the FoB wouldn't have stayed dead? Considering it is apparently Jack after all...