Friend of mine just posted this on Facebook. Thought it was funny.
I found it interesting that most of the main cast have starred with Heath in past movies.
-The above picture from "10 things I hate about you" with Joseph Gordon Levitt and Heath
-Anne Hathaway costared with Heath on "Brokeback Mountain"
-Maggie Gyllenhaal's brother was also in "Brokeback Mountain" with Heath. Maggie probably knew Heath before "The Dark Knight" too
And then we have Bale and Oldman who worked with Heath on "The Dark Knight"
There's a video on youtube of Bale choking up at the MTV movie award when footage of Heath came up too.