I remember watching Heart of Ice for the first time and being amazed at everything--the voices, the animation, Batman himself. I think it's still my favorite episode.
They had some good lines too, which surprised me when I bought the DVD, not remembering terribly much about the show.
"Chance, Grace. Chance is everything. Whether you're born or not, whether you live or die, if you're good or bad....it's all--arbitrary."
"Think of it, Batman--to never again walk on a summer's day with a hot breeze in your face, and a warm hand to hold? Oh, yes...I would kill for that."
"Half of me wants to strangle you."
-"And the other half?"
"Hit you with a truck!"
-"We used to date."
I also liked how they didn't give the Joker an "origin," as with every other villain--it made him a cut above the rest, I think.
Very good work all around. TNBA had its moments, BB I never got into, but I liked Return of the Joker. And Justice League is very nice throughout.
I'm just sorry it's over.