Marvel- the FF fan in me wants to say Dr. Doom, but I have to go with Green Goblin.

DC- The Rogues

Bane is my all-time favorite. Juggernaut, Harley Quinn (Does she actually count as a villain these days?), Venom (Eddie Brock), Deathstroke, and Blackheart are all runner-ups.

DC - Either Poison Ivy or Riddler
 
Marvel - Magneto

always liked the villians, that if you look at things from their perspective and their in the right but everyone sees them as villians like Lex Luthor, Jason Todd, Superboy Prime, Sinestro and Magneto just to name a few.

@RedK said:

always liked the villians, that if you look at things from their perspective and their in the right but everyone sees them as villians like Lex Luthor, Jason Todd, Superboy Prime, Sinestro and Magneto just to name a few.

Agreed. I can never get behind the "MWAHAHAHAHAHA I'm goig to blow up the world!" guys.  My favorite is Ra's for the record.

Poison Ivy always has been since Batman & Robin.

The Joker, for a guy who is "specially sane", reading and watching him makes him seem lovable. If he were real, I'd probably be cowering in fear if we were in the same room.

I have a few....but I've always liked Black Adam

Joker, nuff said.

joker, otherwise venom.

movie wise the Joker was done really well. Comic wise I've always been morbidly fond of Apocalypse. You know something big is going down whenever he is involved.

Babs got great taste, too bad she's gone. Ra's al Ghul is one of the best villains in comics./

PJ Maybe has shot up into 1st place for me over the years

You just can't help but respect the guy for his intelligence and resourcefulness, and he has waay more charisma than any serial killer should ever have, one minute he's funny, the next frightening.

The guy managed to escape the Judges, fake his death, steal a rich guys identity, run for mayor of Mega City 1 (and win), and carried on killing random people whilst in office, and not only that, but he got Mega City 1s unemployment and crime rate waay down, and raised the cities productivity whilst doing it!

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If we're just talking Batman villains though, I'd have to go with the obvious answer and pick Joker.

taskmaster, black manta, joker, norman osborn, venom, prof. zoom, posion ivy, scarecrow.

I always liked Killer Croc, Black Adam is a close second

I have always liked two face

Atrocitus, Black Manta, Captain Cold, Mr Freeze, Riddler, Johnny Sorrow, Eobard Thawne, Norman Osborn, Mysterio.

Green Goblin, Joker, and Deathstroke

Riddler

Joker easily.