I probably wouldn't start with The Killing Joke, since that's best if you already know the characters somewhat.
^ Ah, good ol' BTAS. I'll bet everyone here has a favorite episode or two, but I'll point out some of the best that you just have to watch.
- Heart Of Ice
- Joker's Favor
- Laughing Fish (the comic story this is based off of is also a pretty good introduction to Joker himself)
- Feat Of Clay
- Mad as a Hatter and Perchance to Dream
- Riddler's Reform
- Two-Face
- Clock King
- Vendetta (and, for that matter, A Bullet For Bullock)
- Baby Doll
- Almost Got 'Em
- Beware The Gray Ghost
- Harlequinade
- Harley's Holiday
- Joker's Wild (but seriously, screw AKOM)
- Robin's Reckoning
- The Demon's Quest
- Fear Itself
- The H.A.R.D.A.C. storyline
- The Strange Secret of Bruce Wayne
- The Cape And Cowl Conspiracy (even if the bad guy is a Riddler knock-off).
- Shadow of the Bat
The rest of the episodes are amazing, don't get me wrong, it's just that these dozen and a half or so what I'd figure are the cream of the crop. Character introductions, certain characters' best moments, some of the best oneshot adventures, etc...
Impulsive instinct tells me to advise you to avoid The New Batman Adventures, but... eh. You'll be fine, as long as you avoid episodes that showcase Batsy's newfound lack of personality. And Love is a Croc - I have no idea what they're thinking. In general, there's four TNBA episodes you have to see.
- Holiday Knights.
- Growing Pains
- Over The Edge
- Mad Love
Assorted other TNBA episodes are pretty good as well, I suppose. Knight Time, Joker's Millions, er... Legends of the Dark Knight, Beware The Creeper...
And though I consider it more of a Superman episode, World's Finest. Watch it. Watch World's Finest, for the love of god. Up there with Subzero and Mask of the Phantasm as my favorite DCAU specials/movies.
edited 28th Jun '12 3:58:33 PM by KnownUnknown

While waiting to see if I can find a better condition copy of The Long Halloween, I've started BTAS.
Joker escaping Arkham with a rocket Christmas tree. Wow...
But don't give up hope. Everyone is cured sooner or later. In the end we shall shoot you.