F said, "It's got Uncle R in it!" - Indeed, there is a bit of a resemblance between Anne's little brother and Christopher Ecclestone.
That was excellent. An existential Dalek, no less! The back-story of the Time War comes into clearer focus. The mutant inside was, as autopope put it, "suitably squamous and rugose, not to mention dripping with mucus". The three-way relationship between the Doctor, Rose and the Dalek. (Oh yeah, and Adam. Who is a bit pretty.)
I look forward to finding out what lies behind the phrase "Bad Wolf"...
Edited to add - go read the discussion over at swisstone's.