Y'know, I know how popular the Heath Ledger Joker from The Dark Knight was/is, but I can't even imagine the Joker not sounding like Mark Hamill's version. Dude has the best crazy laugh(s). And on those occasions I read Joker dialogue in the comics, it still sounds like him in my head regardless.
Just in case you're wondering like I did when he tossed the sign out of the "Jokermobile," it said "WAN THE CIRIN GNAL JOKERNOCILE." No seriously.
(I kinda wanted to type "osmemetically" [i.e. "osmotic" plus "memetic" gets "osmemetic"] in the title, but decided against it. Even though I think it's a great word. At least I can claim I coined the word.
It still counts as coining a word if you discover later someone else did first, right?)