Personally, I thought it was a fairly weak opening last night. The new Doctor's introduction was ridiculous. She fell from the Tardis after regenerating and despite falling all that way on to a train, landed completely unscathed! However, Doctor 6 (Colin Baker) regenerated after falling over in his TARDIS!
I just didn't like the story, it all felt a bit rushed in the end. I hope it'll pick up in the coming weeks.
Another point: What I don't understand is how no-one on Earth knows who The Doctor is?
In the past 13 years (since the series was re-launched) we have had a huge number of massive incidents here on Earth, including a spaceship clipping Big Ben and crashing in to the Thames, the Cyermen and Daleks collectively attacking Earth and filling the skies and also The Master controlling everyone's brain, cloning himself and becoming Prime Minister. The Doctor (in various guises) has saved the World on numerous occasions over the past decade or so, and yet when he/she meets people, they have absolutely no idea who he/she is!