I really would like to know what your favorite episode is and why that is. :D There was probably a topic about this already but it's so barried that Its probably worth doing again. -w-
As for my Fav. it would have to be the first episode and the non-original pilot. I love this show dark humor and all and that shows it's true colors right off the bat.
Most shows that I have watched especially in the cartoon world is that the piolt is not that well done and that it takes time to get into the show. However that is not the case with Invader Zim, I can literally watch that one episode and love it just as much as the rest of the show. It put it's best foot forward and kept on running! XD .....until....Never mind.. T^T