The Family Guy vs. The Simpsons debate has been raging for a while, so vote for your favorite. I threw in some other choices too, just in case those aren't your cup of tea. If you have another favorite, say so.
My two cents: The Simpsons, despite their decline, will always reign supreme. Seasons 3-8 are completely untouchable, even against the best Family Guy has to offer. Family Guy jumped the shark after it came back, and is just a parody of itself (South Park's "Cartoon Wars" was so dead on that I can hardly enjoy Family Guy anymore). I think my basic ranking of "adult animated shows" would look something like this:
1. The Simpsons
3. Tie: Aqua Teen Hunger Force and Venture Bros.
4. South Park
5. Family Guy
6. Sealab 2021
7. American Dad
So, let the bloodshed begin!