If I may, I'll start.
I was a huge fan of SUPER FRIENDS, and other DC animated projects, but I think the real start for the proper DCAU was the Timmverse, which incorporated BATMAN: TAS, SUPERMAN: TAS, BATMAN BEYOND, and JUSTICE LEAGUE, as well as BATMAN: MASK OF THE PHANTASM, and several other Batman animated films.
The best series, for me, would be a tie between BATMAN and JL. The best animated films would be MOTP, as well as JUSTICE LEAGUE: DOOM, JL: THE NEW FRONTIER, and BATMAN/SUPERMAN: PUBLIC ENEMIES. The worst series would be, of course, TEEN TITANS GO, which is a horrible bastardization of the much better TEEN TITANS series. Then THE BATMAN, which was just poorly done. The worst movie was SUPERMAN/DOOMSDAY, but only because there was so much of the comics that got cut for running time (I still haven't seen THE KILLING JOKE, but I've been told it's not good). In fact, that would be my real complaint about most of the animated films, that they cut too much from the source material, or changed characters or situations simply for the audience. But, in the end, I feel that if these films get people to read comics, then they are doing their job.