Threadomancing here, but if anyone ever checks this thread looking for a recommendable series or two, they should consider:
First off seconding
The Wire and
Dexter - definitely two of the best ever made
Breaking Bad - curious who hasn't watched this one yet; excels at delivering both drama and suspense elements; generally superior to most non-comedy
True Detective and
Hannibal - grim and morbid atmosphere, high production values and again awesome suspense; top tier cast in both
Sherlock - Sometimes witty, sometimes bland, but always good for a smile; BBC's best right after Doctor Who (or better, depending on your preferences); some really good acting here, too; classic Sherlock Holmes cases in modern day London; first episode is cheesy, but it picks up from there
The Killing (Forbrydelsen) - avoid the US remake of the same name if you can; US one is good, but doesn't even come close to the complex characters of the Danish original; every character involved is a suspect at some point, making for a tense guessing game; can't praise this one enough
The Bridge (Bron) - Again, the American remake is inferior and, in this case, downright sucks imo; the DK/SWE original, however, is beyond awesome - only 2 seasons and the first one starts slow, but once this one gets rolling, it's up there with the big names; has the multidimensional characters typical for Danish crime/drama hybrids
Borgen - Another Danish one and some great drama here. Revolving around the Danish parliament (which sounded pretty dry to me), this one's a true classic with mean cliffhangers; politics made interesting and thrilling
The Shield - A little more on the action side of things when compared to The Wire and the characters seem more onedimensional, but definitely recommendable; was getting better and better with each season and has a nice season-overarching story. Funny how one get to symathize with the protagonist pretty early on despite him being a complete prick most of the time.
Hustle - Another BBC production; this one's more lighthearted and family-friendly; quality varies from episode to episode, but most of it was widely enjoyable; some good hints if you're fancying a career as a con artist
Luther - feels like a modern Noir flick; slightly foreseeable here and there, but mostly a good filler thriller; still deeper than any of the CSIs & co out there
Bounced off
The Walking Dead and
Game of Thrones, but people keep trying to convince me those were awesome.
If you can enjoy a good anime from time to time, as someone else mentioned,
Death Note's plot is hard to top.
If you want Gibsonesque 90s cyberpunk meets drama, try
Serial Experiments Lain.
Ergo Proxy,
Ghost in the Shell SAC and
Gungrave round up the list.