My problem with Batman TAS is I have to remember that it's for kids because, otherwise, the writing just makes my eyes roll. Although I think Dini, the writer behind Asylum and Arkham City, did pen some of the more interesting episodes, and you can usually tell they're his because they play around with structure.
Visually, is it amazing and, of course, the music is great. It just irks me to see Batman do an face or fail in some of the ways he does. That's probably more down to the comics and films though. Interesting that the series spawned Renee Montoya and Harley Quinn though.
Anyway, if I recall, Talia's first appearance is in Off Balance, which was a fairly good episode.