spetznaz
Senior Fanboy Killer
This is actually trickier than most people are giving it credit for, and a very good thread to be honest.
You have Lex Luthor, a machiavellian adept who is the guy you find under the definition on nietzchean malevolent (Friedrich Nietzche must have had a far flung vision of future DC comics depicting Lex when he started writing his philosophies ....even though that was long before there was anything like DC comics).
Lex is not only INCREDIBLY brilliant, but he has access to a very diversified array of resources (Lex actually has the most diversified resource base for HUMANS in comics, ranging from high tech Earth technology, to various alien tech suites, to even fourth dimension technology from Apokolips). He also has the sheer strength of will to be able to pull through against vast odds, which is why even though he is a human he is a challenge to the gods (i.e. Superman and others).
However, the Joker is not a funny man in a clown suit.
The guy is also amazingly bright (by some measures as bright, if not more, than Bruce Wayne), and you could characterize his madness as super-intelligence run amok (it was insinuated once that that was what it was).
While Lex is able, through pure force of will and resources, to get almost anything done; the Joker is also able to do the same, but unlike Lex's machiavellian approach of guile and subterfuge, ol' Joker uses an obtuse string of far-flung stratagems that seem stupid, at first, but in the end come together in a brilliant manner.
Let me put it this way ....if I was Lex i would NOT want to nuke where I BELIEVED the Joker to be. The reason is, I would not be able to confirm if the Joker is actually dead (since everything would be vaporized) ....I would rather have a situation where i see the cold body of the Joker, not a tepid belief that the Joker was SUPPOSED to be within the mile-wide area that i just nuked.
The reason is taking the Joker for granted is an easy way to get killed.
Who would win?
I honestly cannot call this, since both of them have amazing advantages going for them. However, only one of them has a slight (slight, but still present) disadvantage.
The moment Lex Luthor takes the Joker for granted, using his belief that he has all sorts of tech (as some are, well ...correctly, saying) and that will protect him from a 'clown,' then he will die.
Because, while Lex can easily come up with an Apokoliptan battlesuit, the Joker is someone who could just show up with Doomsday or Kal (controlled in more or less the way Ivy was doing it) ....or against all odds, show up by your bedside with a bread knife and ill intent ....
This was a better thread than most people were giving it credit for, by the way.