Breaking Bad/ Mad men
House of Cards
Fringe/ American Horror story
The walking dead
dexter/ homeland
the wire
Game of Thrones/ Boardwalk Empire
lost
the blacklist
arrested development
archer
sherlock
spartacus
the office/parcs and rec
californication
Downton Abbey
Luther
Listen to Dev and fill in the rest of the HBO catalog. Sopranos, Oz, Band of Brothers, Six Feet Under, Deadwood and Rome are some quality shows. Some of the best of all time. Carnivale, too, but its cancellation is heartbreaking. True Blood is campy and raunchy, but incredibly entertaining. A bit inconsistent but worth the watch. Eastbound and Down is great if you're a fan of that type of Comedy. The Newsroom is really good too. Don't forget some of HBO's mini series like Band of Brothers, Generation Kill, John Adams and The Pacific to a lesser extent.
- Sons of Anarchy has been consistently good to great since its first season.
- The Shield is excellent.
- Justified is fucking great.
- Have you seen 24? If not, watch it now. It's ridiculous at times, and the later seasons (outside of the awesome last season) are misfires, but it's so damned entertaining and addicting.
- Person of Interest
- Sleeper Cell. If you like Homeland or 24, watch this fucking show. It's only a 2 season commitment, but it's really good.
Recent shows that are quality: Banshee, Strike Back, Bate's Motel, Hannibal, Ray Donovan, Top of the Lake, Vikings, Orphan Black, The Americans, The Bridge, Hell on Wheels. It's being remade, but do yourself and watch the original The Returned.
British shows (I hate British humor, so don't look to me for recommendations within the genre): Misfits, Life on Mars, Sherlock, State of Play, Mad Dogs, Black Mirror, Spooks/MI-5, The Fall, Utopia, This Is England ’86/’88, Ultraviolet (Idris Elba is in it), Dead Set and Southcliffe
Season One then BAIL THE FUCK OUT: Heroes and Prison Break.
Comedies: It's Always Sunny in Philadelphia, Real Husbands of Hollywood, The League, Louie, Curb Your Enthusiasm.
Canceled shows (ie. Awesome shows, short commitment): Firefly (If you like Whedon, Buffy and Dollhouse are good shows, with the latter fitting within this category), Arrested Development (no longer the case though), Twin Peaks, Jericho, Terriers, Freaks & Geeks/Undeclared, Dead Like Me/Pushing Daisies/Wonderfalls (Poor dude can't catch a break) and Day Break. The Borgias was really good too.
Science Fiction: Battlestar Galactica (last season is weak, but the show leading up to that is excellent), Fringe, X-Files and Stargate SG-1. My other recommendations depend on how much you like Science Fiction, and how nerdy you are. Star Trek: The Next Generation (Stars off weak and is inconsistent, but its' highs are REALLY high), Deep Space Nine, Babylon 5 (The first season is legitimately shit, but make it through that and enjoy some masterful television).
Quality Mini series that haven't been mentioned: The Lost Room, The Pillars of the Earth, Hattfields & Mccoys, Taken, Mildred Pierce, Carlos, "I, Claudius, Pride and Prejudice, Lonesome Dove, Shaka Zulu, Shogun, The Red Riding.
Non-American/British shows: City of Men (Basically City of God: The TV show), Äkta människor/Real Humans (Pretty interesting Scandanavian sci fi show), Borgen, Underbelly (Aussie Sopranos), Spiral (Quality french crime show), Forbrydelsen/The Crime (The original The Killing), Riget/The Kingdom (Lars Von Trier show), Edge of Darkness (original show the movie with Mel Gibson is based on).'
I think I'm done...