Family Guy is great, and there are a lot of RI references that some people probably miss.
The Simpsons was funny when I was a kid. In the late 90's it started to feel really repetitious and trite. It was terrible for a few seasons, then when it came back, it seemed like they were trying to be edgy due to the success of South Park, but falling FAR short. It was like they wanted to push the envelope, but didn't have the balls to do what South Park did. Or maybe they were afraid of looking like Johnny-Come-Latelies. Either way, the Simpsons never recovered. Like SNL, the first seasons were so good that people keep watching, hoping it'll come back to it's former self. But it won't. I do want to slap SNL and Simpsons fans, because it just seems like brand loyalty at this point. But unlike NVidia or ATI fanboys, the product is not worth fanatics.
Futurama is great, especially for dorks. All the philosophy, math and physics references interspersed with enough absurdity to make it not mentally taxing... Great stuff...
Robot Chicken is good, but I have to be in the mood for it.
The Brak Show and Aqua Teen Hunger Force are my current favorite cartoons. As I get older my taste for absurdity grows, and nothing delivers like Brak or the Aqua Teens. If it isn't ridiculous to the point of incoherence, it's not funny.