Beast Wars: Transformers. An awesome and well written show, and also the finest example of Transformers storytelling (along with its sequel, Beast Machines).
posted over a year ago
It also has some of the best opening music I've ever heard for a cartoon.
Total Drama, Ed Edd N Eddy, Invader Zim, Regular Show, Adventure Time, My Little Pony: Friendship is Magic, The Amazing World of Gumball and others. :)