we have Cesar Romero from the 1966 series, Jack Nicholson from Batman 1989, or Heath Ledger in The Dark Knight 2008? This is much harder that the Batman choice due to each played a great character. I'm gong to go with Cesar Romero he always cracked me up as a kid. Second is Jack he was really good and maybe it's because I was only 11 when I saw it but he convinced me he was CRAZY. Heath Ledger was really good also but I can only have one favorite.