I do like South Park. Especially early episodes, much like the Simpsons.

However, more recently, they've been focusing much more on pop culture- that is, current events, marketing, current people, and after a while, it gets annoying. Kind of like they don't have much fresh material, so they extend on what's going on currently.

Family Guy has been known to "steal" things from other episodes of other stuff, but aside from that? It's funny in its OWN way.