This summer I've been running Changing Breeds from (Old) World of Darkness. Campaigns I've run in the past year (in nor particular order):
Old World of Darkness (OWoD)
7th Sea
Legend of the Five Rings (L5R)
Serenity
Marvel (that's right. 1980's TSR)
All Flesh Must be Eaten
By Campaign I mean more than one game was played sequentially with the same character(s)
As for Batman: I'd really like to see them do the Mad Hatter next. It would play greatly along with the whole psychotics theme. Penguin and Mr. Freeze you can almost sympathize with if they didn't commit crimes, and villains like Clayface, Poison Ivy, Bane, Croc, and Catwoman are more about getting what they want while involving as few people as possible (that is, they don't go out of their way to make people part of their plots. Except for one Ivy arc I remember). I would like to see a Harlequinn but I don't know how they'd go about things. Rupert Thorn or Scarface (that puppet with the schizophrenic ventriloquist) would be good tie-ins to the mob theme they've got going on (asusming they didn't pull him in already in some small insignificant way).