Redeemed Villains in Batman

[CylonsKlingonsDaleksOhMy]

So something I've noticed in Batman comics (and nowhere else) is that so many of his rogues end up being redeemed. (And then comics come in and retcon that, of course, but that's business.)

Riddler became an ally (featured in Gotham Sirens and some other places)
Bane became a tenuous ally (teaming up with Bruce to investigate Thomas Wayne)
Poison Ivy was a tenuous ally (Birds of Prey, Gotham Sirens)
Clayface (Detective Comics Rebirth)
Killer Croc (Batman Eternal)
Two-Face was cured for awhile (Hush and One Year Later)
Amygdala (Nightwing)

Talia al Ghul and Catwoman have ALWAYS been back-and-forth on the line of morality.

I find these story arcs incredibly compelling when Batman's villains find redemption, and it always disappoints me when they inevitably go back to being enemies. (But again, that's comics; status quo is king.)

Anyone else?