King of the Hill has never been funny, ever. Maybe it's cause I'm Canadian, but honestly? I just don't get it. I don't know why it's on TV.
And I really think the Simpsons needs to end. It's running on a concept from the late 80's / early 90's, and trying to make it work forever is just making it painful to watch. I've always liked Futurama much more than the Simpsons because it had a really fresh concept (mind you, they're bringing it back next year a la Family Guy so we'll see if it gets stale too).
I'm a giant Family Guy fan, but I'm not writing this from a biased point of view or anything. Family Guy is really appropriate for this day and age. It's 2007 (not 1989, Simpsons!) and people are sick of the same old things, and want something fresh, honest, and just plain funny, which Family Guy is. It's just right for what's going on in the world right now because it has no pretenses, and everyone and everything is spoken about and made fun of, and it's poignant while being freaking hilarious at the same time. And it's only been on 5 seasons (going on 6), not 25 million.