Only just come across this thread now, but thought I would chime in with some shows that I've encountered over the years.
Luther: British crime drama with Idris Elba from The Wire, starring as a brilliant but troubled detective solving cases. Also explores the peculiar relationship he has with a suspected killer of a case he was investigating, but he could not convict her. Must watch if you are a fan of Elba.
Parade's End: Adapted from novels that, admittedly, I've not read, about a love triangle between a conservative upper class Brit, his vindictive wife, and a young suffragette, set against the backdrop of World War I. Stars Benedict Cumberbatch, so I watched it for him primarily as well!
Rome: Before there was Game of Thrones, on HBO there was Rome; a show about Rome at the height of its reign. It is told from the point of view of the noble families vying for the throne, and the rest of society, but specifically from the pov of two men who are soldiers. Terrific British ensemble cast, as we see some of them in Game of Thrones currently, i.e. the GoT characters Edmure Tully, and Mance Rayder are played by the actors who players Brutus, and Julius Caesar respectively.
John Adams: A historical drama about the USA's journey towards becoming independent, following one of the founding fathers John Adams, played by Paul Giamatti. I'm sure some artistic liberties were taken with the depiction of history, but still interesting nonetherless. And some great performances by this group of actors and actresses. Stephen Dillane as Thomas Jefferson was especially great.
