Manu good ones already listed i pickef a couple i haven't seen yet.
Of current American cartoons i think one of the best running is Gravity Falls.
I really liked the green lantern series, sadly short lived, Grey Delise did a great job on aya's voice. I actually talked to her on twitter and she did my voice mail in thst voice. She does this for charity now and then.
Batman the animated series was really good in the 90's.
Courage the Cowardly Dog
Avatar: The Last Airbender
SpongeBob SquarePants
Adventure Time
Teen Titans
Kim Possible
Foster's Home for Imaginary Friends
Danny Phantom
Codename: Kids Next Door
Invader Zim
Ben 10
Lilo & Stitch: The Series
Xiaolin Showdown
ChalkZone
My Life as a Teenage Robot
6teen
The Emperor's New School
Total Drama Island
Hamtaro
Action League NOW!