I think Time Magazine got it right, even the runners-up and the show at #1.
http://entertainment.time.com/2012/12/04/the-top-10-tv-shows-of-2012-the-best-and-the-rest/For the lazy to click...
10. The 2012 Election (various channels)
9. American Horror Story (FX)
8. Parenthood (NBC)
7. Game of Thrones (HBO)
6. Girls (HBO)
5. Mad Men (AMC)
4. Breaking Bad (AMC)
3. Homeland (Showtime)
2. Louie (FX)
1. Parks and Recreation (NBC)
Runners-up:
Archer
Awkward
Bunheads
Boardwalk Empire
Bob’s Burgers
Community
The Daily Show
The Good Wife
Gravity Falls
Happy Endings
LA Complex
Late Night with Jimmy Fallon
Justified
Luck
Masterchef (I can’t justify this. I just really enjoyed it this year.)
Nashville
New Girl
Nurse Jackie
Sons of Anarchy
30 Rock
Treme
Wilfred
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Personally, I'd add Suits and Spartacus to the list of runners-up.