Besides some german sitcoms (that are actually adaptions of british and american formats, I think), I really enjoy Scrubs, The Big Bang Theory, Family Guy and South Park (though I think that the newest season so far doesn't quite catch up to the others).
1st - Community (gets 1st over Happy Endings for being so endlessly ambitious and having sitcom characters I actually care about)
2nd - Happy Endings (probably actually slightly funnier than Community)
=3rd - 30 Rock
=3rd - Outnumbered
5th - Modern Family
Others that aren't on the air any more or have gone so far downhill they might as well not be:
15 Storeys High
Scrubs (the 9th season never happened)
Better Off Ted
And just to shake things up, here's some of the worst :
Two and a Half Men (worst ever)
Big Bang Theory
Mike & Molly
Well, I don't watch TV very much these days, but I used to be a huge fan of Friends. I have seen every episode over a hundred times. In spite of having said I don't watch TV very much, I guess I do have a few recent sitcoms that I tune into every now and then. Parks and Recreation, The Office, Nurse Jackie, Weeds, and The Big C are among my favorites. I am WAY behind, but I try to catch up online (on Hulu, etc.) when I have extra time on my hands. I've been considering ordering DVD box-sets of all the episodes if catching up online proves too inconvenient.