I'm excited about the prospect of Futurama returning, but if it doesn't happen I'll be satisfied watching the old ones over and over (finally got some of the DVD's).
Whilte I like Family Guy very much, I just think Futurama is on another level. I think Valin's right on the mark describing FG as "gag-driven". That can get old after awhile, but Futurama seems to get better the more I watch it. I also love the countless references to various sci-fi works.
One thing I like about Futurama compared to Simpsons and FG is that it sometimes (though rarely) gets really serious--almost depressing. Remember the episode with Fry's fossilized dog? The first time I saw that episode I was shocked at how intense it got. Another example is the "Luck of the Fryish" episode. That Breakfast Club music gets me every time

(Hope I didn't spoil anything for any Futurama newcomers.)
-Matt