The Wire is the best series out there.
True Detective and The Newsroom also excellent.
The Blacklist and Elementary are a little less 'serious', but still worth watching. The Following was also decent, with that Kevin Bacon.
Only one I'd add to an already large list is The Leftovers. Season 1 has not long finished, and although i have no real idea what is going on, it's compelling stuff - much like Lost was. Looking forward to season 2.
Got Fortitude on my planner which looks good too.