Actually that's # 99 Circus. And at # 100, I have to add the following. It's too important and influential to be ignored and who doesn't love those Halloween specials? - The Simpsons
http://www.youtube.com/watch?v=VUOpTd568oQJase, I'm glad you nominated "The Simpsons". I've been watching this thread, not participating, just waiting to see how long it would take someone to mention it. I guess the fact that people forgot about it reflects how far the quality has sunk in the last few years. Seasons 2-4 were by far the funniest, most subversive, and most clever program on TV at the time, and made all of the "adult" cartoons that followed marketable.
I was gonna nominate it, but honestly thought somebody did already. In all honesty, the show still has good moments/episodes. Nowhere near the quality it was during seasons 1-8, but better than other shows out there, like American Dad and Family Guy. I like Family Guy, but wow.
I figured South Park would've made the list too. The quality of shows they CONTINUALLY put out is great.