Ohh, definitely. There are certainly more popular shows, and shows that have made more money (I think), but nothing is as far-reaching as The Simpsons.
I was born in '98, and it was definitely the show. One of my mates had Foxtel (woah -- big deal!), and I remember being excited as they showed The Simpsons on Fox8 a lot.
My favourites were always the Halloween ones! My top one is Treehouse of Horror XIV, where Homer kills the Grim Reaper, Milhouse and Bart find a magical stopwatch, and Professor Frink reanimates his father.
Another of my favourites is where we find out that Homer is only an idiot because he has a crayon stuffed up his nose. When he takes it out, he is revealed to be a genius. However, he alienates his family and friends, so he decides to put it back in for their happiness. It made young-me sad.
Just something more to add: I prefer early Simpsons to early Futurama, but I prefer late Futurama to late Simpsons. Futurama also has more emotional episodes (see: 'The Luck of the Fryrish', 'Jurassic Bark').