Classic/no longer running:
The Wire/The Shield, Skins, The Sopranos, Fringe, Band of Brothers/The Pacific, Spaced/Black Books, Deadwood, Oz, Rome, Firefly, Rescue Me, Monk, Curb Your Enthusiasm, Freaks and Geeks and for god's sake Spartacus: Blood & Sand.
Great and still running:
Homeland, Mad Men, Breaking Bad, Game of Thrones, Boardwalk Empire, Girls, Enlightened, Treme, Dr. Who, Downton Abbey, Justified, Venture Bros, Archer, The Americans, and Louie.
Pretty decent/tolerable and still running:
Veep, Parks n' Rec, Arrested Development, It's Always Sunny in Philadelphia, Sons of Anarchy, Dexter, Wilfred, Psych, and True Blood.
I'm not sure which category Cougar Town goes under.