The Joker first and foremost. He's one crazy-ass, magnificent bastard. Then there's Deadpool and the Batman himself.
As for publishers, I haven't had enough exposure to comics yet to pick one. There's probably something for me in either of them.
Hurr Durr Derp said:
2 Things:
1: As you live pretty close to where I live, I wonder where you get your comics. I fail to find a proper shop other than b-b-b-bol.com.
2: Mind recommending a Constantine comic? Before this thread I only really knew him from the movie, but damn in the comics he seems to be a Harry Dresden on steroids with some Deadpool mixed in between. I like him already.
Mind you, I'm (sadly) a comicbook newb and have only read a couple of them and only own 2; The Killing Joke and Deadpool Classic Volume 2.