Just picked up and started on BTAS season 1, and I f***ing love it. I used to watch it in the afternoons, and Danny Elfman's score still gives me the chills. It's got a very "you're done with school today and you're gonna watch something cool now" vibe. Just awesome, and not mentioned enough. I remember what a breath of fresh air this series was in the world of animation. The respect for the material and the attention to detail was unparalleled and unprecedented at the time. I remember thinking, omg you can actually see how and where and when punches are thrown! They animated everything!
And there was talk before about the too-similarity of the Timmverse character designs, and i just wanted to chime in and say that I think it was kind of a stylistic choice throughout, based on the BTAS designs of this gothic, art-deco stuff which suits the material SO well. It didn't work as well for some of the later incarnations because they took the art-deco style and added sunshine and brighter colors, and it just works better if it's dark. If you want to see Supes done well with art-deco, look up the old Fleischer Superman cartoons. The dialogue is corny as hell but it's BEAUTIFUL to look at. You can see them for free on itunes in the "vintage cartoon" podcast.