Well the sitcoms I enjoy are mostly confined to FX. Louie is by far the best comedy going, It's Always Sunny is always a good watch, The League would probably be lost on you. HBO is getting rave reviews on Girls which I haven't watched and I'm not sure on, but Veep is fucking hysterical if you know the slightest about american politics and the old standby of Curb Your Enthusiasm. Comedy Central has some good shows and some clunkers.
Broadcast is a different story though. NBC has about 4-6 sitcoms that are critical darlings that I haven't watched(or anyone else for that matter) Community, Parks and Rec, The Office, 30 Rock. ABC has the same deal with Happy Endings, Don't Trust the B, Modern Family, The Middle and Suburgatory all shows that I might like if I'd actually bother watching them. But the rest of their comedy lineups are shit. CBS is pure formulaic bullshit like 2.5 Men, Mike and Molly, Big Bang, HIMYM. Fox has one night of comedy and one night dedicated to Seth McFarlane.