What surprised me the most is that Dumbledore was much more conflicted than he appeared to be in the previous books. Loved the Snape and Lily storyline, and feel vindicated that Snape was on the right side, but I really expected either Ron or Hermione to die.
The epilogue, far too short and other than Albus Severus, not really surprising. I wanted to know a little more other than they married and had children and that Neville became Herbology Prof.
Kreacher was a nice twist too, didn't see that coming, except for one hint from J.K.R. to leave Kreacher in the Order of The Phoenix movie.
Sybil used her balls.
Molly channelling Sigourney in Alien