I didn't count the New Batman Adventures as separate from Batman: The Animated Series because despite the change in style of animation and the new & extended characters I still consider The New Batman Adventures to be Season 4 of Batman: The Animated. The same applies to both Justice League & Justice League Unlimited. I mean I guess they're technically two different shows due to th change in theme song but I think I may consider JLU to be Seasons 3,4 & 5 of JL.
1) Batman: The Animated Series
2) Justice League
3) Superman: The Animated Series
4) Batman Beyond
5) Static Shock
6) The Zeta Project
FYI I have never actually seen the Zeta Project but I'm just gonna make an educated guess that it might be my least favourite.