Honourable Mentions to (Either I haven't seen them but they'd be on here probably, or there's no room): TBB Season 2, The Wire, Greys, 90210, Suits, Mad Men, and The Sopranos.
3) Lost - So I was SUPER young when this first aired (6 years old in 2004 IN FACT!) but watching it back it's AMAZING. It does have a rep for being hard to follow, but truly I do love it just for it's entertaining value, it's emotional death value, and having a great set of characters.
2) Game of Thrones - I hate to be one of THOSE guys like "OMG U HAVENT SEEN IT?!??!?!? WTFFFFFFFFF WATCH IT OR ELSE UR SO BAD AND BAD AND BAD WORD BAD!" but it's just so perfect, it's gone a bit boring compared to series 3-5 atm but that was expected when it overtook the books
1) The Office (US) - Just absolute perfect, I love it SOOOOOOO much and everything about it is so perfect. A show you can watch at ANY time and ANY episode and still laugh. Dwight and Jim are 2 of my favourite people to ever be written and I wouldn't change it for ANYHING.