Really, John Stewart? Might I ask why?
I don't read enough comics to know a lot of characters but here goes anyway...
Hawkgirl (Shayera from the JLU cartoons, don't know how she acts in comics)
Rogue (even though I don't read X-Men, is she evil now or what?)
Huntress (my Goddess, she's gorgeous)
Batgirl (Babs and Cassie)
Superman (whatever, I like the guy, the most powerful being on Earth and he refuses to take advantage of us, that's pretty admirable in my book, I'd abuse that power in a sec :P )
Mr Freeze (yeah, I know, but when the dude decides to do the right thing it's usually to save Batman's life
Green Lantern (they're all pretty cool)
Batman (meh, I needed a filler
Just kidding Bruce...please don't monitor me...again...
Captain America (he's frikkin' Captain America! Plus, he talks funny
Scarecrow and Mad Hatter (they're hilarious together)
Most criminals (...as they get their brains blown or stomped on by Punisher)