I like Family Guy. I also really like American Dad and The Cleveland Show too.
The show I really miss though, is Futurama. That was a great show. If you like the show, be sure to check out all of the DVD movies made, there were at least 4 straight to DVD Futurama movies made.
While Family Guy is generally funnier, I think I actually prefer to watch American Dad for it's humor, which isn't quite as crude, most of the time. In my humble opinion, Roger the Alien is the funniest character out of all the shows.