Deadwood is my favorite series of all time.
11-22-63 was my favorite short series of 2016.
Quarry is a very good neo noir series, but you need to let it develop a bit.
Boardwalk Empire was great.
The Australian series Underbelly was great to very good for the first 3 or 4 years. You can see a sample here -
&index=13 .
The BBC series Luther is a very good quick one.
Gomorrah is a great Italian series in the vein of The Sopranos. It just started rebroadcasting on American Tv (Sundance), but you can find the first 3 seasons on Putlockers, etc.....
The Corner from HBO was like a proto The Wire, you might like it. You can see the episodes here -
www.youtube.com/watch?v=9Paz0ajIxzI .
Mad Men is great, I'd recommend block viewing though, never found it to be a good casual show because the plots are so interwoven.
Oz was fun if you've never seen it.
Lilyhammer was a fun, and quirky series, once you give it a chance.
Ray Donovan is very good, but the last season left a good amount to be desired.