I agree Sarah, and I do think (and hope) that there is going to be something different about this Christmas as opposed to just another Cyberman attack.
I re-watched the finale and read the news this morning that some people hated the the end-
Click.
I thought the end was heartbreaking, a far sadder situation than the end of series two knowing she had changed so much and discovered so much about herself and become so important and had such inventions...to lose it all and go back to an existence where she will probably never amount to anything.
The Rose/fake doctor was uncomfortable and not quite right, it felt wrong...and that's what was so good about it she didn't know if it was right either. I loved Donna, I hope the next companion is something a bit different again.