It is my duty to inform people that Garth Marenghi's Darkplace is the human race's greatest accomplishment in the art comedy, and it's only six episodes long so everyone should watch it. Find it on YouTube, this is the kind of show that's meant to be watched at 480p.
Other than that, Breaking Bad is definitely my favourite show. Yes, I know it ended almost two years ago. No, I'm still not over it. Despite all of the other shows out there, it's something I still feel I need to re-watch again at some point.
Most of my other favourites seem to be comedies, like Arrested Development and It's Always Sunny in Philadelphia (I actually only started watching this earlier this year. Haven't seen the newest season yet.). As far as older shows go, Fawlty Towers is also really really funny.