The first Pirates of the Caribbean movie was way better than I expected. So, I voted for it's sequel.
I'll definately go see the third X-Men movie. So, I guess it comes in 2nd (they pick some dumb names for these though).
Superman Returns is 3rd. Honestly, I don't know much about it. I've never been a big Superman fan. I guess Kevin Smith was supposed to write it at one point and it fell through.
The Da Vinci Code might be cool, but I haven't read the book. So, I don't know much about it. I suppose I don't think of this type of movie as a "blockbuster".
I don't know much about Cars or Poseidon. I remember liking the first Poseidon movie, but I think I saw it when I was 10.
Mission Impossible 2 sucked. I have no interest at all in Mission Impossible 3.