I need to watch The Wire. I've heard too many people rave about it now.
In no particular order:
Six Feet Under
Arrested Development
Breaking Bad
Mad Men
House
Futurama
Battlestar Galactica
The Good Wife
The Amazing Race
It's Always Sunny in Philadelphia
Honorable mentions: Curb Your Enthusiasm, The Walking Dead, The League, Modern Family, Downton Abbey, Sherlock