Sonic the Hedgehog (the one kinda based off the Archie Comics one).
In all seriousness (though STH was pretty good), I liked the FOX X-Men and Spiderman shows. I loved the crossover they did between the two. And that "Legend of Wolverine" DVD they came out with had some great eps.
I'm loving B:TAS a lot though. I think it's pretty long lasting overall, and I loved the Animated Moves that came out of them,
especially Phantasm. And Kevin Conroy is just badass.
Nowadays, JL, Teen Titans, and the oldie but still goodie X-men Evolution (why did you cancel it?! Bastards!).
JL is one of the best, with it's great stories in the two episode one hour shows that Cartoon Network
used to do before going back to just showing one each. Some great arcs there, like the one with the Justice Lords, Wild Cards (gotta love that ending), and others who's titles I can't remember offhand.
Teen Titans is good too, and is better than I originally expected it to be, though sometimes the "chibi" thing gets pretty annoying. But overall some good stories, and Robin's conflict with Slade was awesome, especially in the "Apprentice" storyline. (MINOR SPOILER:
"I have a father..." *pan up, lightning flash, bats flying* ). That was a Great TV Moment for me.