You know, "canceled" implies a top-down decision that the show sucks and must be terminated. A better word might be "finalized." The last few seasons have definitely not had the same appeal as the first ten (in my opinion anyway), but it keeps on going. The longer something is on the air, the less good it becomes, so why not just give it a rest when the once lovable yellow people still have some appeal left? One last episode, showing them 20 years from now (in a non-scifi setting), how their lives have changed, etc, and give it some closure. I'd say the series deserves at least that much.
Oh, and if Futurama got axed for being slightly less awesome in its later seasons, The Simpsons ought to be as well.
