I was practically raised on Pokemon and The Simpsons, so those two. Honorable mentions are Johny Bravo, Cow & Chicken, Loony Toons (kind of a given), Dexter's Laboratory, and Tiny Toons Adventures. Keep in mind I don't mention Avatar the Last Airbender or non-Pokemon anime since I was somewhat older when Avatar started and I didn't really watch Toonami as a kid.