Rose 'dies' in the finale.
I say 'dies' because it's generally accepted that Rose will die, given what The Beast said about the 'valiant child who dies in battle'. But the producers have said it'll all be very vague and open. They've admitted that Piper is leaving, but Rose's exit - while technically a death - may not be a proper Death.
My guess is that the Time Vortex pops back up.
I say that because while I'm sure you've all noticed the 'running theme' thing this series is the mention of Torchwood in each episode (New Earth excluded) - I doubt many of you noticed that last season's theme of 'Bad Wolf' has also been popping up, indicating that the Bad Wolf (merged Rose/Vortex) may have made more changes to the timeline than simply wiping out the Daleks.
The two most notable references were when the werewolf said Rose had 'something of the wolf about [her]' and in the latest episode where the Torchwood database's information on Rose had been corrupted by 'the Bad Wolf virus'.
So I'm guessing the Bad Wolf made some connection with Rose in whatever timeframe the finale takes place and her 'death' is something along the lines of merging with the vortex permenantly.
