Dash Baxter(Danny Phantom): I had to admire this jerk, for the sheer fact that he manages to win so often. He also made me laugh. Truthfully, he was more interesting than the hero. (Heck, he's in the opening title!)
Seto Kaiba(Yu-Gi-Oh!): He was the reason I watched Yu-Gi-Oh(Duel Monsters dub). [Eric Stewart: great job!] Just watching the kid's corporate goings-on was a blast. He's also handsome, has cool ETERNALLY WAVING CLOTHING, and a soft spot for his little brother. Finally: the Blue Eyes White Dragon. This anime teen wails on Dash, takes HIS lunch money, and burns it because he, Kaiba, is inordinately Scrooge McDuck wealthy.
Slingshot(G1 Transformers): He kind of needs his attitude to keep up with the likes of G1 Starscream.
Dr. Braxis(Challenge of the Gobots): The voice of Rene Auberjonois. The fact that he outlasted Dr. Arkeville on THE OTHER TRANSFORMING ROBOT SHOW. The fact that the giant robots were the least of his concerns on that wacky show as time went on.
I can't think of too many cartoon jerks offhand that I like. Only one's an out-and-out villain(aside from Kaiba giving Sugoroku(solomon/grandpa) a heart attack after ripping the fourth BEWD in half!).
There's also Donald Duck(at times): he invented the genre.