I'm not a huge Joker fan (he's probably 4th or 5th on the list of the Bat Rogue's gallery in terms of appeal), and griming him up in an attempt to make him more realistic and scary doesn't add to the character's appeal. And Ledger definitely deserves to be tweaked for his preparedness for the role: locking yourself in a hotel room and living off room service for a month is goofy no matter how you slice it, and excessive for any part. Read "Mad Love" and "Killing Joke", watch some of the Dini/Timm cartoons and Romero gad about madly, and one can get the gist of the character.

And as I aid in my original post, despite my misgivings about Ledger I think the trailer still looks good, and look forward to seeing the movie itself.