Modern Family is my favorite right now. I also like How I Met Your Mother and The Big Bang Theory.
The Office is my all-time favorite show though.
Some more while I go down memory lane:
and one more recent one
Ones I've been meaning to get to when I have time:
The Office (US)
Parks & Rec
Jane, stop this crazy thing!
Radio News (all time favorite)
Northern Exposure (stretching it a bit to call it a SitCom)
Star Trek, the original series (stretching it a lot ...)
Used to love Three's company, Redd Fox show, and other 70's sitcoms.