Only just came across this thread and notice the first post says 'what to watch on Netflix' but there's a lot posting series from Prime, BBC etc so here's my non-platform specific picks:
The Sopranos
House of Cards - watched this prior to the Kevin Spacey revelation so I can imagine watching this from the start and knowing what we now believe to be true about him would change the experience a lot, but this show was one of the most gripping i've ever watched at the time
Stranger Things
Peaky Blinders - Captivating series i'm sure many on here will have seen already but Cillian Murphy is quality, as is Tom Hardy and latterly Adrien Brody. Strong BBC content.
True Detective - Series 1 is maybe the best single series of a show I've ever seen - Woody Harrelson and Matthew Mcconaughey are absolutely class. Series 2 is pretty terrible (luckily they're stand-alone so no need to bother with this one), and Series 3 was really strong again.
House
Narcos
Breaking Bad
Band of Brothers - Tom Hanks and Steven Spielberg's 120 million dollar collab - I've watched all 10 episodes maybe 5 or 6 times through now and it still hasn't got old.. The attention to detail in these shows is unreal, & the budget they put into each episode was pretty much unheard of 20 years ago (not so much not with Netflix & HBO chucking tens of millions into shows like Game of Thrones). The Pacific came next and apparently had a bigger budget than BoB but didn't quite hit the same highs as the first series. Still well worth watching mind..
Chernobyl - Very late to the party on this one, and at times found it very hard to watch but incredibly detailed and accurate account of the events surrounding the explosion of the reactor. I've a friend who's teaching over in the Ukraine and she says that it's far more accurate than the Russians would have us believe.
They Shall Not Grow Old - Although not a series, this is special. Peter Jackson remasters Black and White World War One footage to tell the true story of life for a soldier at that time, told by people who fought themselves.
Brooklyn 99
Black Books
Spaced
The IT Crowd
Peep Show
Mighty Boosh
I've never got round to watching Power or The Wire but am told they're pretty special shows..