If Heath Ledger were alive today, and able to respond to the constant comparisons fans make regarding his portrayal of the Joker to Jack Nicholson's portrayal of the Joker, this is what I think (imagine) he would say:
"The Joker of The Dark Knight would not exist as he does if it wasn't for Jack's vision of the Joker in 1989. Same goes for the Jack's Joker compared to Cesar Romero's Joker; which can then further be compared to the comics version and so on and so on...comparisons as to which Joker is 'better' is both a waste of time and disrespectful to all the actors who have played the Joker. Now lets get something to eat!"
Apparently Heath Ledger is hungry.