Vaguely spoilerish of The End of Time.
So, the mysterious Woman in White... who is she?
We see her at the end as one of the dissenting high council Time Lords. The Doctor obviously recognises her, in a very meaningful way. Apparently some people are suggesting she's the Doctor's Mother. Others, that she's Rose (WTF?). I briefly thought she was somehow a future Time Lady version of Donna--this was helped along by a significant glance the Doctor gave when he was asked about her. But honestly, that's lame. My actual theory?
Romana. The Lady Romanadvoratrelundar. Honestly, she had that air about her. And interfering like that is JUST like her. And when asked to identify herself she only responded 'I was lost... a long time ago.' Reference to E-space? 'Course it could just mean the Time War and be anybody, but still.
Mostly I just want Romana back. :)
Anyway, general comments on the episode(s): Good riddance, RTD. You write good dialogue, and you understand the characters well, but half your plots suck. I'll forgive you the forced, hole-filled plot of this one, though, for the sake of that lovely ending. Thank you sincerely, and welcome Steven Moffat!