My humble submission to this thread
1. Breaking Bad
Perhaps the greatest show ever aired. Everything about it is absolute tense perfection. The casting, the acting, the writing, the cinematography. It's all grand, and should be held as the current high water mark of television.
2. The X-Files
Comeon. It's the X-Files. I could talk about it, but everyone here probably knows about it and loves it already (you better love it

). Also gets props for being directly responsible for Breaking Bad.
3. The Wire
If there's one show that can top BB on writing and story, it's this. A drama centering on the Baltimore drug trade, as shown from the perspectives of everyone from the street dealers, to the police, all the way to the mayors office. Complicated and intriguing. Three thumbs up.
4. Arrested Development
Are you serious?
Almost always. I was once voted the worst audience participant Cirque Du Soleil ever had.
5. Game of Thrones
A show about a bunch of incestuous, backstabbing, powerhungry bastards willing to kill everyone they know and love so they can be the one to sit on an uncomfortable looking seat made out of swords. Also it has the most kick ass oversexed dwarf to ever exist, some little dragons, and a naked boob every 10 minutes.
Honorable mention: Lost.
It drifted towards the end, but it still held me in thrall during it's entire run. Gotta give it props.