Harley Quinn, seasons 1 and 2: I really loved this. Basically the Venture Bros. meets Batman: The Animated Series. In some ways, it seems like a small thing, but it feels so much more right when the villains can actually swear properly and kill people. And talk about sex, for that matter*. Some cool plots, strong arcs in each season, and actual character development. Great cast, too, with Ivy, King Shark, Bane, and Clayface as the major standouts for me. Alan Tudyk actually holds his own in the inevitable comparison with Mark Hamill's Joker, which is impressive. My only real issue is, basically, that it ended where I wanted it to start. Or in other words, I really hope we get a couple more seasons.
*Nothing explicit, but it's just that they can, for instance, actually say outright that Ivy and Kite Man are having sex, rather than just referring to it obliquely with the fact that they're dating.