Okay, I've seen plenty of DC villain threads, but let's narrow it down a bit here. Batman has some of the most famous adversaries in comic history, so I think these baddies getting their own thread isn't too much to ask for.

Personally, I think my favorite is Harley Quinn. She ranges from the Joker's goofy jester sidekick in B:TAS to the biker themed masochist in Arkham City, but I think my favorite portrayal is by far the original. I can't help but adore someone who's only real motivation for being bad is love, no matter how delusional. She has a great back story, has some of the best episodes in the series, (Mad Love was moving and Harlequinade was hilarious) and she gets more laughs out of me than the Joker himself.  

Also, I think the Joker/Harley relationship is one of the more ones in the whole mythos.

Honorable mentions go to Two-Face, Joker, and Bane. (Depending on the incarnation. Comics Bane was good, TDKR Bane was flawless, but most cartoon versions of him I think abandon his intelligence for the sake of making him a boring, big bruiser.)

 

I could be predictable, and say Joker. But i'm gonna say Scarecrow is my favourite. It wasn't really until Cillian Murphy's portrayal in Batman begins that I understood the potential the character had, and then playing Arkham Asylum I realised just how great he was as a villain. Sure he's not much of a fighter, physically, but his experiments in terror and the mind make him a great villain. So much so I threw a Batman party for my birthday, and had a costume in the spirit of the Arkham games made.

 

My favourite villain is arguably one of the most sinister and cunning of Batman's rogue gallery. With the help of The Riddler and Scarecrow, he hatched a magnificent plot to end Batman, that involved mainpulating several other villains. This plot nearly ended the Dark Knight for good several times, and brought about such events as Batman revealing his identity to Catwoman, and the return of Jason Todd. He is named for the rhyme "Hush, Little Baby" and is an intensely personal enemy straight from Bruce's childhood.

He is Tommy Elliot, a.k.a. Hush.

 

Scarecrow! Been my favorite since I was a kid. Love the Fear thing and his look. Its cool he's getting used alot more lately in several different comics...and will be part of the new Secret Society of Supervillians!

 

I'm most familiar with Batman from the Animated Series. My favorite villain was Clayface. I just liked his powers the best. Actually, he was about the only Batman villain I recall who even had super powers. Killer Croc was probably my second favorite.

 

My number one is Harley Quinn. (Derp) She was a really fun and complex character in B:TAS, and I enjoyed every moment of her in the Joker/HQ episodes. Arleen Sorkin really steals the show when she's portraying Harley. The Arkham games made her more interesting, to me. I didn't care for her costume in Asylum, but Arkham City's incarnation was great. She was goofy while still being a sadistic maniac. I hope she does more come Arkham 4 and maybe Origins.

Second is Scarecrow. I like how he's not quite insane, just devoted to his experiments. The origional incarnation in the old cartoon was kinda doofy, but Cillian Murphy's Scarecrow showed how Scarecrow is cool. He's no expert in hand-to-hand, but is still a threat with his fear gas. Asylum's Scarecrow was incredible. His parts in the game are always a fun thing to play through, and Dino Andrade's portrayal made the experience better. I hope he wrecks shit up in Arkham 4.

Third is probably Riddler or Deathstroke. Riddler is a really fun character. His constant tries to make himself better than Batman is a great trait. His Arkham incarnation is especially good, especially when you get to City. Wally Wingert is the perfect voice for him. Deathstroke is really cool in concept alone. He's an extremely durable hitman. What's not to love?

 

BANE! He broke Batman!

 

1. Joker - He's the most well known Batman villain for a reason, because there's no other villains quite like him
2. Harley Quinn - Like Joker her motivation for crime isn't because she just wants to do bad things and that makes her interesting
3. Bane - I like his portrayal in the Knightfall series, that his intellect is what makes him so deadly and not his brawl and brute strength
4. Mr. Freeze - He has one of the best backstories for any comic book character
5. Catwoman - Best love/hate relationship between her and Batman in the comics, perhaps ever

 

I liked the Riddler. He just seemed more fun than, say, the Joker.

 

I absolutely loved the way that Scarecrow was portrayed in Arkham Asylum, I was so disappointed when he didn't appear in Arkham CityCertainly hopes he makes an cameo in Origins!

Nobody could ever replace Arleen Sorkin.

"Oh c'mon puddin'! Don't ya wanna rev up your Harley? Vroom vroom!"  

 

The Riddler. He's just an interesting villain. Or perhaps Ra's ah Ghul, mostly because of Batman: TAS.

 

Poison Ivy, especially since she got the green skin. She puts the sexy in eco-terrorism.

 

it's a toss up between Scarecrow and Clayface. If I had to choose one it would be Clayface just for his power alone, although the big problem with Clayface is that there is like 6 different people who took up the name in the comics.
I also really like Bane (the comic/arkham games).

 

My favorite is Mr. Freeze because he has a really sympathetic backstory and great character design. I am also pretty fond of Hush and Deadshot too.

 

Joker. Don't care if it's predictable, he's Batman's equal, the only villain who consistently challenges Batman. He always takes him to the brink of sanity, and he almost always gets the best story arcs.

 

Well, Deathstroke is also on equal ground with Batman...

 

Penguin-He only Batvillian that always dress sharp and had Penguin-Theme Weapons.

 

Deathstroke has never inflicted the mental harm on Batman Joker has.

 

The Joker. Growing up watching TAS, his Characterization being voiced by Mark Hamill was Absolutely Spot-on.

A Close Second would have to be Two-Face. While Tommy Lee Jones' Performance in Batman: Forever was decidedly over-the-top eccentric ("LET'S GET THIS PARTY STARTED WITH A BANG!"), His Depictions in The Dark Knight and Batman: The Animated Series were worthy of praise.

 

That is true. Deathstroke just matches Bats in combat.