i know st. peter won't call my name.
These are my theories that I have for The Oncoming Finale™. I'm actually about 95% unspoiled for what's going to happen so none of this can be considered spoiler-y. Just speculative.
1. Harriet Jones has something to do with The Master and is in league with The Daleks. There are a few things that add up to this in my mind: Harriet Jones does not like The Doctor at all because of what he did to her (this was also mentioned in the episode), The Master's drum beat can be heard as she was trying to get through to everyone on the subwave, This Is Gallifrey could be heard earlier in the episode (this was played in the YANA parts of Utopia and also at The Master's funeral pyre), they focused on The Hand In A Jar for a little too long, she knew about The Osterhagen Key and you never actually saw her be exterminated.
Now, I'm not quite sure what's going on there with that but she was wearing a ring in her scene (now, I don't know if it was the ring) and there was a hand that picked up the ring at the end of Last Of The Time Lords so maybe she picked it up and now she's mind-sharing with The Master?
Another thing that leads me to (sort-of) believe this is that the BBC released a lot of stuff on Davros previous to the episode and they don't usually do that with The Big Bad. Maybe they were putting that much focus on Davros to distract from the real Baddie - The Master.
I know this sounds fairly cracky but remember, this is Russel T Davies and Doctor Who we're talking about. Anything can happen.
2. The Time War is going to feature heavily. The mentioned it quite prominantly by saying that it was "Time Locked" in the episode. Martha has a key. Maybe this key can unlock The Time War? (This would also fit quite nicely in with my theory of Harriet Jones/The Master as she knew about the key and didn't want Martha to use it.) Or if things can fall through into it... things can come out? This would leave room for Gallifrey to return, if not now then in one of the specials next year.
3. I have no idea what to think about this key. Osterhagen is an anagram os "Earths Gone" and we all know how much RTD likes his anagrams and other word fuckery (Torchwood, YANA) so it might be something to do with that. She was told to only use it if "no help is coming" so it's gotta be pretty big.
3b. Osterhagen is German for "burning man" apparently. I have no idea what this could mean. Possibly something to do with The Doctor (re: all the comparisons between The Doctor and fire.)
4. Now, I now for sure that he isn't regenerating so it's just a matter of how they're going to get around that issue. Dalek Caan mentioned that "The Threefold Man" was coming, so maybe The Doctor's going to split into three parts. Either 3 of Ten or Ten and two other previous incarnations. Sylvester McCoy and Peter Davidson being in The Confidential so maybe a Five&Seven split? (I really doubt that this will happen but I CAN HOPE OKAIS)
4b. I've heard the theory from some of fandom *cough*batchippers*cough* that there'll be two Ten's and one will stay with Rose in Pete's World. For the record: I would actually turn off my tv and that happens and throw an epic fanbrat tantrum and only return to Who with Moffat at the helm. This wouldn't just down down to my deep aversion to Rose/Ten but it goes against everything that this show has stood for since the beginning. DO NOT WANT.
5. This is a fairly common theory that Jack will take Mickey and Martha back to Torchwood. I don't know how I feel about this. I used to hate the idea but now I'm kind of coming around to it. If it's done right, it could be my favourite thing ever and I adore Jack and Martha chemistry. But then you've got the fact that Torchwood is it's own show and by dumping old Who companions into it, it's kind of defeating the point.
6. The "most faithful companion's" everlasting death. I don't know who this is but I'm going to be pissed at whoever it turns out to be (although I very much doubt that anyone's going to actually die). Even if you only take the New!Who companions: SJS carried on the work years and years after Four abandoned her. Rose wouldn't leave Nine and went back into danger after having looked into the TARDIS. Jack waited for over a hundred years for him and rebuilt Torchwood. Martha stayed with him in 1913, 1969, walked around the post-apocolyptic world for a year alone and now works for UNIT. Donna killed herself in Turn Left in order for the world to go back to normal and I'm sure she's got something coming in the finale.
So whichever is dubbed ~most faithful~ is going to royally piss me off. I didn't even mention all the Old!Who companions. By giving one of them that title it's completely undermining the importance of all the others and k9 IS TOTES HIS MOST FAITHFUL COMPANION ANYWAYS.
7. Donna's heartbeat was totally The Drums. Something's going on there and also "the loss that's yet to come". A lot of people are talking about her being a Time Lady *cough*Romana*cough* but Chameleoned or The Master. I don't know how I would feel about either of these things because a big part of Donna's charm is that she's human (like, far more human than Rose Tyler The Most Human-y Human Ever) so I want them to keep it that way.
We do know that she's only signed for one season so something bad's going to go down. My feeling is that they probably won't kill her, but The Doctor's going to be left with no choice other than to wipe her memory a la Jamie and Zoe.
(They got retconned because Gallifrey ordered him to so that would also fit in nicely with my Gallifrey-will-return Theory Of Hope.)
SO THERE YOU HAVE IT. All the thoughts that I have. Do any of you have any theories in particular, cracky or otherwise? I'd love to hear them *g*