I'd rather the trailer with Potter than with Pirates, if only because I will see Potter in the theater, and, God willing, I will never set eyes on Pirates 3.
EVER.
So I would then have to download the TDK trailer to watch it, instead of seeing it on the big screen.
And to people dismissing the Harry Potter movies: I did too, until I actually watched one. Let me tell you, they are VERY good movies and VERY good books, and they are more than just kid's stories. the first couple are aimed at a younger audience, but JK Rowling seems to be smart enough to realize that between books, her audience is growing up, so each Harry Potter book is more mature in subject matter than the one before it - which also makes sense given that the characters are a year older in each story. So they started out at 11 and by the end of "Deathly Hallows" they will be 18.
Each story is not only more adult than the one before it, but darker than the one before it. And while I felt kind of silly watching the first two, by the third one I felt completely different about them. HP5 is a very dark tale indeed.