Catwoman = Recent exposure for the character in TDKR + Her own comic book.
Sinestro = was in a terrible movie, popular from the cartoon, leading role in the Green Lantern comic book at the moment.
Martian Manhunter = No movie (yet) but is still popular from cartoons. Only just being reintroduced to the New 52.
Basically I think that the first two are slightly, ever so slightly, more accesbile/recognizable to non-comic book or non-comic cartoon fans. But yeah, MMH should be in, he could have a really unique, decent playstyle