Surprised this has never been done.
Gonna be pretty boring and go...
1) The Sopranos
2) The Wire
3) Boardwalk Empire
Some people might not think Boardwalk's up there, but yeah, i do. Ticks all the boxes for me - gangsters, prohibition, gruesome murders, tits, cinematically goodm well written, nice pace, more tits. Aye. Like.
I've tried getting into Breaking Bad and Mad Men, but i just find them a bit boring.
Stuff like The Shield and 24 was never really more than okay-ish, imho.
Have started the first series of 'Homicide: Life on the Street' and quite like it.
Quite fond of NYPD Blue, too.
All-time top threes then (please don't say Twin Peaks)...