LMP
Blue Crack Supplier
Depends on which way you want to go. Buscemi would be funnier, but Glover would make it much creepier.
I think Buscemi can capture that manic, obsessive quality pretty well. The Riddler's always been a campy character; it'd be toned down in the film, of course, but he can sell both sides well. Glover would be creepy as shit, that's for sure. I'd be fine with either of them getting it.
I'd only recommend Elijah Wood after seeing Sin City... goddamn.