For only eight minutes of the new Doctor and Billie, the future certainly looks good. She's got that wary WTF is happening expression down beautifully, and he's just so... different. And bouncy! And mad! And so equally fun to watch avidly as was Christopher Eccleston. And he has a mole. *smirks* David and Billie are already bouncing off each other in a most delightful, yet different fashion - the moments when he took her hand and the point he got her to smile particularly stood out. I'm fairly sure I heard wildecate's shouts of glee at that point. ;)
Lovely throwaway Captain Jack line - didn't hear it completely, but I think it was along the lines of "Oh, he'll be alright - he's got the whole of Earth to repopulate!".
Great stuff, and I think the most telling sign is that I so wanted to watch more.