I've noticed that every episode of Everybody Loves Raymond has a very similar plot.
Namely, Ray's wife does everything she can to make his life miserable, while Ray makes whining noises.
I don't think I've ever seen a single episode of Everybody Loves Raymond.
Also: Cheers was pretty good… but yeah, I have to say I think the Simpsons is pretty much the best half hour show of all time. It's got all levels of satire, humor, insight into the culture… and its influence is pretty much universal. You can't really beat it, even if it's not as good anymore.
Frasier for the definite win!
Scrubs was pretty funny in the early seasons.
Malcolm in the middle is good too; I got my brother to watch a couple of episodes when he was little and from that point on he called every fly Tony
Fawlty towers is excellent!
The freaking funniest scene ever in a sitcom!
[video=youtube;pvn-tBeLpCk]http://www.youtube.com/watch?feature=player_detailpage&v=pvn-tBeLpCk[/video]
Arrested Development - Stellar acting; great use of callbacks, foreshadowing, reality subtexts; very high joke-density; rewarding even after multiple viewings etc
Community - Unconditional love needs no motivation. It's good, okay?
Bored to Death (questionable if the term sitcom applies) - The way the show smiles and nods at nihilism and warmly embraces insecurities makes it exceedingly cozy.